diff --git a/core/src/avm1.rs b/core/src/avm1.rs
index 45d00b58f..39e69e08b 100644
--- a/core/src/avm1.rs
+++ b/core/src/avm1.rs
@@ -440,7 +440,12 @@ impl<'gc> Avm1<'gc> {
                         object.call(self, context, object.as_object()?.to_owned(), &args)?;
                     self.stack.push(return_value);
                 } else {
-                    let callable = object.as_object()?.read().get(&name);
+                    let callable = object.as_object()?.read().get(
+                        &name,
+                        self,
+                        context,
+                        object.as_object()?.to_owned(),
+                    );
 
                     if let Value::Undefined = callable {
                         return Err(format!("Object method {} is not defined", name).into());
@@ -659,14 +664,19 @@ impl<'gc> Avm1<'gc> {
                 if let Some(clip) = node.read().as_movie_clip() {
                     let object = clip.object().as_object()?;
                     if object.read().has_property(var_name) {
-                        result = Some(object.read().get(var_name));
+                        result = Some(object.read().get(var_name, self, context, object));
                     }
                 }
             };
         }
 
         if result.is_none() && self.globals.read().has_property(path) {
-            result = Some(self.globals.read().get(path));
+            result = Some(
+                self.globals
+                    .clone()
+                    .read()
+                    .get(path, self, context, self.globals),
+            );
         }
         self.push(result.unwrap_or(Value::Undefined));
         Ok(())
@@ -1133,10 +1143,10 @@ impl<'gc> Avm1<'gc> {
             Self::resolve_slash_path_variable(context.target_clip, context.root, var_path)
         {
             if let Some(clip) = node.write(context.gc_context).as_movie_clip_mut() {
-                clip.object()
-                    .as_object()?
+                let object = clip.object().as_object()?;
+                object
                     .write(context.gc_context)
-                    .set(var_name, value);
+                    .set(var_name, value, self, context, object);
             }
         }
         Ok(())
diff --git a/core/src/avm1/globals.rs b/core/src/avm1/globals.rs
index 99c2cde9f..fe8eec7fa 100644
--- a/core/src/avm1/globals.rs
+++ b/core/src/avm1/globals.rs
@@ -52,9 +52,9 @@ pub fn random<'gc>(
 pub fn create_globals<'gc>(gc_context: MutationContext<'gc, '_>) -> Object<'gc> {
     let mut globals = Object::object(gc_context);
 
-    globals.set_object("Math", math::create(gc_context));
-    globals.set_function("getURL", getURL, gc_context);
-    globals.set_function("random", random, gc_context);
+    globals.force_set("Math", Value::Object(math::create(gc_context)));
+    globals.force_set_function("getURL", getURL, gc_context);
+    globals.force_set_function("random", random, gc_context);
 
     globals
 }
diff --git a/core/src/avm1/globals/math.rs b/core/src/avm1/globals/math.rs
index 78703d700..ecceddc02 100644
--- a/core/src/avm1/globals/math.rs
+++ b/core/src/avm1/globals/math.rs
@@ -6,7 +6,7 @@ use std::f64::NAN;
 macro_rules! wrap_std {
     ( $object: ident, $gc_context: ident, $($name:expr => $std:path),* ) => {{
         $(
-            $object.set_function(
+            $object.force_set_function(
                 $name,
                 |_avm, _context, _this, args| -> Value<'gc> {
                     if let Some(input) = args.get(0) {
@@ -49,14 +49,14 @@ pub fn random<'gc>(
 pub fn create<'gc>(gc_context: MutationContext<'gc, '_>) -> GcCell<'gc, Object<'gc>> {
     let mut math = Object::object(gc_context);
 
-    math.set("E", Value::Number(std::f64::consts::E));
-    math.set("LN10", Value::Number(std::f64::consts::LN_10));
-    math.set("LN2", Value::Number(std::f64::consts::LN_2));
-    math.set("LOG10E", Value::Number(std::f64::consts::LOG10_E));
-    math.set("LOG2E", Value::Number(std::f64::consts::LOG2_E));
-    math.set("PI", Value::Number(std::f64::consts::PI));
-    math.set("SQRT1_2", Value::Number(std::f64::consts::FRAC_1_SQRT_2));
-    math.set("SQRT2", Value::Number(std::f64::consts::SQRT_2));
+    math.force_set("E", Value::Number(std::f64::consts::E));
+    math.force_set("LN10", Value::Number(std::f64::consts::LN_10));
+    math.force_set("LN2", Value::Number(std::f64::consts::LN_2));
+    math.force_set("LOG10E", Value::Number(std::f64::consts::LOG10_E));
+    math.force_set("LOG2E", Value::Number(std::f64::consts::LOG2_E));
+    math.force_set("PI", Value::Number(std::f64::consts::PI));
+    math.force_set("SQRT1_2", Value::Number(std::f64::consts::FRAC_1_SQRT_2));
+    math.force_set("SQRT2", Value::Number(std::f64::consts::SQRT_2));
 
     wrap_std!(math, gc_context,
         "abs" => f64::abs,
@@ -73,8 +73,8 @@ pub fn create<'gc>(gc_context: MutationContext<'gc, '_>) -> GcCell<'gc, Object<'
         "tan" => f64::tan
     );
 
-    math.set_function("atan2", atan2, gc_context);
-    math.set_function("random", random, gc_context);
+    math.force_set_function("atan2", atan2, gc_context);
+    math.force_set_function("random", random, gc_context);
 
     GcCell::allocate(gc_context, math)
 }
@@ -96,7 +96,7 @@ mod tests {
             fn $test() -> Result<(), Error> {
                 with_avm(19, |avm, context| {
                     let math = create(context.gc_context);
-                    let function = math.read().get($name);
+                    let function = math.read().get($name, avm, context, math);
 
                     $(
                         assert_eq!(function.call(avm, context, math, $args)?, $out);
diff --git a/core/src/avm1/movie_clip.rs b/core/src/avm1/movie_clip.rs
index 10966792f..42db33e3d 100644
--- a/core/src/avm1/movie_clip.rs
+++ b/core/src/avm1/movie_clip.rs
@@ -6,7 +6,7 @@ use gc_arena::MutationContext;
 macro_rules! with_movie_clip {
     ( $gc_context: ident, $object:ident, $($name:expr => $fn:expr),* ) => {{
         $(
-            $object.set_function(
+            $object.force_set_function(
                 $name,
                 |_avm, _context, this, args| -> Value<'gc> {
                     if let Some(display_object) = this.read().display_node() {
@@ -25,7 +25,7 @@ macro_rules! with_movie_clip {
 macro_rules! with_movie_clip_mut {
     ( $gc_context: ident, $object:ident, $($name:expr => $fn:expr),* ) => {{
         $(
-            $object.set_function(
+            $object.force_set_function(
                 $name,
                 |_avm, context, this, args| -> Value<'gc> {
                     if let Some(display_object) = this.read().display_node() {
diff --git a/core/src/avm1/object.rs b/core/src/avm1/object.rs
index 0a1a3e10d..97cd092d7 100644
--- a/core/src/avm1/object.rs
+++ b/core/src/avm1/object.rs
@@ -2,7 +2,9 @@ use crate::avm1::{ActionContext, Avm1, Value};
 use crate::display_object::DisplayNode;
 use core::fmt;
 use gc_arena::{GcCell, MutationContext};
+use std::collections::hash_map::Entry;
 use std::collections::HashMap;
+use std::mem::replace;
 
 pub type NativeFunction<'gc> = fn(
     &mut Avm1<'gc>,
@@ -24,10 +26,83 @@ fn default_to_string<'gc>(
     Value::String("[Object object]".to_string())
 }
 
+#[derive(Clone)]
+pub enum Property<'gc> {
+    Virtual {
+        get: NativeFunction<'gc>,
+        set: Option<NativeFunction<'gc>>,
+    },
+    Stored {
+        value: Value<'gc>,
+        // TODO: attributes
+    },
+}
+
+impl<'gc> Property<'gc> {
+    pub fn get(
+        &self,
+        avm: &mut Avm1<'gc>,
+        context: &mut ActionContext<'_, 'gc, '_>,
+        this: GcCell<'gc, Object<'gc>>,
+    ) -> Value<'gc> {
+        match self {
+            Property::Virtual { get, .. } => get(avm, context, this, &[]),
+            Property::Stored { value, .. } => value.to_owned(),
+        }
+    }
+
+    pub fn set(
+        &mut self,
+        avm: &mut Avm1<'gc>,
+        context: &mut ActionContext<'_, 'gc, '_>,
+        this: GcCell<'gc, Object<'gc>>,
+        new_value: Value<'gc>,
+    ) {
+        match self {
+            Property::Virtual { set, .. } => {
+                if let Some(function) = set {
+                    function(avm, context, this, &[new_value]);
+                }
+            }
+            Property::Stored { value, .. } => {
+                replace::<Value<'gc>>(value, new_value);
+            }
+        }
+    }
+}
+
+unsafe impl<'gc> gc_arena::Collect for Property<'gc> {
+    fn trace(&self, cc: gc_arena::CollectionContext) {
+        match self {
+            Property::Virtual { get, set } => {
+                get.trace(cc);
+                set.trace(cc);
+            }
+            Property::Stored { value, .. } => value.trace(cc),
+        }
+    }
+}
+
+impl fmt::Debug for Property<'_> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            Property::Virtual { get: _, set } => f
+                .debug_struct("Property::Virtual")
+                .field("get", &true)
+                .field("set", &set.is_some())
+                .finish(),
+            Property::Stored { value } => f
+                .debug_struct("Property::Stored")
+                .field("value", &value)
+                .finish(),
+        }
+    }
+}
+
 #[derive(Clone)]
 pub struct Object<'gc> {
     display_node: Option<DisplayNode<'gc>>,
-    values: HashMap<String, Value<'gc>>,
+    values: HashMap<String, Property<'gc>>,
     function: Option<NativeFunction<'gc>>,
     type_of: &'static str,
 }
@@ -58,7 +133,7 @@ impl<'gc> Object<'gc> {
             function: None,
         };
 
-        result.set_function("toString", default_to_string, gc_context);
+        result.force_set_function("toString", default_to_string, gc_context);
 
         result
     }
@@ -80,29 +155,80 @@ impl<'gc> Object<'gc> {
         self.display_node
     }
 
-    pub fn set(&mut self, name: &str, value: Value<'gc>) {
-        self.values.insert(name.to_owned(), value);
+    pub fn set(
+        &mut self,
+        name: &str,
+        value: Value<'gc>,
+        avm: &mut Avm1<'gc>,
+        context: &mut ActionContext<'_, 'gc, '_>,
+        this: GcCell<'gc, Object<'gc>>,
+    ) {
+        match self.values.entry(name.to_owned()) {
+            Entry::Occupied(mut entry) => {
+                entry.get_mut().set(avm, context, this, value);
+            }
+            Entry::Vacant(entry) => {
+                entry.insert(Property::Stored { value });
+            }
+        }
     }
 
-    pub fn set_object(&mut self, name: &str, object: GcCell<'gc, Object<'gc>>) {
-        self.values.insert(name.to_owned(), Value::Object(object));
+    pub fn force_set_virtual(
+        &mut self,
+        name: &str,
+        get: NativeFunction<'gc>,
+        set: Option<NativeFunction<'gc>>,
+    ) {
+        self.values
+            .insert(name.to_owned(), Property::Virtual { get, set });
+    }
+
+    pub fn force_set(&mut self, name: &str, value: Value<'gc>) {
+        self.values
+            .insert(name.to_string(), Property::Stored { value });
     }
 
     pub fn set_function(
         &mut self,
         name: &str,
         function: NativeFunction<'gc>,
-        gc_context: MutationContext<'gc, '_>,
+        avm: &mut Avm1<'gc>,
+        context: &mut ActionContext<'_, 'gc, '_>,
+        this: GcCell<'gc, Object<'gc>>,
     ) {
         self.set(
+            name,
+            Value::Object(GcCell::allocate(
+                context.gc_context,
+                Object::function(function),
+            )),
+            avm,
+            context,
+            this,
+        )
+    }
+
+    pub fn force_set_function(
+        &mut self,
+        name: &str,
+        function: NativeFunction<'gc>,
+        gc_context: MutationContext<'gc, '_>,
+    ) {
+        self.force_set(
             name,
             Value::Object(GcCell::allocate(gc_context, Object::function(function))),
         )
     }
 
-    pub fn get(&self, name: &str) -> Value<'gc> {
+    pub fn get(
+        &self,
+        name: &str,
+        avm: &mut Avm1<'gc>,
+        context: &mut ActionContext<'_, 'gc, '_>,
+        this: GcCell<'gc, Object<'gc>>,
+    ) -> Value<'gc> {
         if let Some(value) = self.values.get(name) {
-            return value.to_owned();
+            return value.get(avm, context, this);
         }
         Value::Undefined
     }
@@ -145,3 +271,109 @@ impl<'gc> Object<'gc> {
         self.type_of
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    use crate::backend::audio::NullAudioBackend;
+    use crate::backend::navigator::NullNavigatorBackend;
+    use crate::display_object::DisplayObject;
+    use crate::movie_clip::MovieClip;
+    use gc_arena::rootless_arena;
+    use rand::{rngs::SmallRng, SeedableRng};
+
+    fn with_object<F, R>(swf_version: u8, test: F) -> R
+    where
+        F: for<'a, 'gc> FnOnce(
+            &mut Avm1<'gc>,
+            &mut ActionContext<'a, 'gc, '_>,
+            GcCell<'gc, Object<'gc>>,
+        ) -> R,
+    {
+        rootless_arena(|gc_context| {
+            let mut avm = Avm1::new(gc_context, swf_version);
+            let movie_clip: Box<dyn DisplayObject> = Box::new(MovieClip::new(gc_context));
+            let root = GcCell::allocate(gc_context, movie_clip);
+            let mut context = ActionContext {
+                gc_context,
+                global_time: 0,
+                root,
+                start_clip: root,
+                active_clip: root,
+                target_clip: Some(root),
+                target_path: Value::Undefined,
+                rng: &mut SmallRng::from_seed([0u8; 16]),
+                audio: &mut NullAudioBackend::new(),
+                navigator: &mut NullNavigatorBackend::new(),
+            };
+            let object = GcCell::allocate(gc_context, Object::object(gc_context));
+
+            test(&mut avm, &mut context, object)
+        })
+    }
+
+    #[test]
+    fn test_get_undefined() {
+        with_object(0, |avm, context, object| {
+            assert_eq!(
+                object.read().get("not_defined", avm, context, object),
+                Value::Undefined
+            );
+        })
+    }
+
+    #[test]
+    fn test_set_get() {
+        with_object(0, |avm, context, object| {
+            object
+                .write(context.gc_context)
+                .force_set("forced", Value::String("forced".to_string()));
+            object.write(context.gc_context).set(
+                "natural",
+                Value::String("natural".to_string()),
+                avm,
+                context,
+                object,
+            );
+
+            assert_eq!(
+                object.read().get("forced", avm, context, object),
+                Value::String("forced".to_string())
+            );
+            assert_eq!(
+                object.read().get("natural", avm, context, object),
+                Value::String("natural".to_string())
+            );
+        })
+    }
+
+    #[test]
+    fn test_virtual_get() {
+        with_object(0, |avm, context, object| {
+            let getter: NativeFunction =
+                |_avm, _context, _this, _args| Value::String("Virtual!".to_string());
+            object
+                .write(context.gc_context)
+                .force_set_virtual("test", getter, None);
+
+            assert_eq!(
+                object.read().get("test", avm, context, object),
+                Value::String("Virtual!".to_string())
+            );
+
+            // This set should do nothing
+            object.write(context.gc_context).set(
+                "test",
+                Value::String("Ignored!".to_string()),
+                avm,
+                context,
+                object,
+            );
+            assert_eq!(
+                object.read().get("test", avm, context, object),
+                Value::String("Virtual!".to_string())
+            );
+        })
+    }
+}