diff --git a/data/sprites/entity/overlay/transform.png b/data/sprites/entity/overlay/transform.png
new file mode 100644
index 0000000000..0bbcd5b922
Binary files /dev/null and b/data/sprites/entity/overlay/transform.png differ
diff --git a/doc/CHANGES.txt b/doc/CHANGES.txt
index 51038ffae4..fdcfb90edc 100644
--- a/doc/CHANGES.txt
+++ b/doc/CHANGES.txt
@@ -19,6 +19,7 @@ Changelog
 - added parallax backgrounds to Wizards Tower
 - added quick menu button to toggle pathfinding via ground
 - added support for animated entity overlay effects
+- added transformation effect to vampires
 
 
 1.47
diff --git a/doc/contributors.md b/doc/contributors.md
index 7b3403a5d4..2762d9dbcc 100644
--- a/doc/contributors.md
+++ b/doc/contributors.md
@@ -998,6 +998,7 @@ The following people released their work to the public with a suitable license f
 * [Inchadney](http://inchadney.com/sounds.html)
 * [Bart Kelsey](https://opengameart.org/users/bart)
 * [David Kvistorf (fluffclipse)](https://soundcloud.com/david-kvistorf)
+* [Aidan Walker](https://opengameart.org/users/aidanwalker)
 <!-- markdownlint-enable -->
 <!-- prettier-ignore-end -->
 <!-- ALL-CONTRIBUTORS-LIST:END -->
diff --git a/doc/contributors/contributors.json b/doc/contributors/contributors.json
index 3e90c4f83c..3d9e51f2bc 100644
--- a/doc/contributors/contributors.json
+++ b/doc/contributors/contributors.json
@@ -4773,6 +4773,10 @@
 			"fullname": "David Kvistorf",
 			"link": "https://soundcloud.com/david-kvistorf",
 			"link_alt": "https://opengameart.org/users/fluffclipse"
+		},
+		{
+			"name": "Aidan Walker",
+			"link": "https://opengameart.org/users/aidanwalker"
 		}
 	]
 }
diff --git a/doc/sources/graphics-entity.txt b/doc/sources/graphics-entity.txt
index 3e2e3eb8d2..5ef5a337da 100644
--- a/doc/sources/graphics-entity.txt
+++ b/doc/sources/graphics-entity.txt
@@ -773,6 +773,7 @@ flame*          DkuCook, Jordan Irwin (AntumDeluge); CC0; https://opengameart.or
 ice_sparkles*   Jordan Irwin (AntumDeluge); OGA BY 3.0 or newer; Stendhal
 magic_sparkles  Rawdanitsu, olonu; CC0; https://opengameart.org/node/18068
 necro_flames    Wolf W. (Ouren), Jordan Irwin (AntumDeluge); CC BY 3.0; https://opengameart.org/node/45981
+transform       Aidan Walker; CC0; https://opengameart.org/node/160840
 
 
 data/sprites/entity/ratfolk/
diff --git a/src/js/stendhal/entity/Creature.ts b/src/js/stendhal/entity/Creature.ts
index 28ac435dcc..7b58ebfbe3 100644
--- a/src/js/stendhal/entity/Creature.ts
+++ b/src/js/stendhal/entity/Creature.ts
@@ -15,6 +15,8 @@ import { EntityOverlayRegistry } from "../data/EntityOverlayRegistry";
 
 import { Color } from "../data/color/Color";
 
+import { SkillEffect } from "../sprite/action/SkillEffect";
+
 declare var marauroa: any;
 declare var stendhal: any;
 
@@ -53,4 +55,17 @@ export class Creature extends RPEntity {
 		return "url(" + stendhal.paths.sprites + "/cursor/attack.png) 1 3, auto";
 	}
 
+	/**
+	 * Shows a temporary animation overlay for certain entities.
+	 *
+	 * FIXME: does not restore previous overlay
+	 */
+	protected override onTransformed() {
+		if (!this["name"].startsWith("vampire")) {
+			return;
+		}
+		const delay = 100;
+		const frames = 5;
+		this.overlay = new SkillEffect("transform", delay, delay * frames);
+	}
 }
diff --git a/src/js/stendhal/entity/RPEntity.ts b/src/js/stendhal/entity/RPEntity.ts
index c131aff7bb..8d33d0a4a0 100644
--- a/src/js/stendhal/entity/RPEntity.ts
+++ b/src/js/stendhal/entity/RPEntity.ts
@@ -102,6 +102,8 @@ export class RPEntity extends ActiveEntity {
 			this.onLevelChanged(key, value, oldValue);
 		} else if (["title", "name", "class", "type"].indexOf(key) >-1) {
 			this.createTitleTextSprite();
+		} else if (key === "subclass" && typeof(oldValue) !== "undefined" && value !== oldValue) {
+			this.onTransformed();
 		}
 	}
 
@@ -848,4 +850,13 @@ export class RPEntity extends ActiveEntity {
 			this._target.onAttackStopped(this);
 		}
 	}
+
+	/**
+	 * Called when entity's subclass is changed.
+	 *
+	 * Does nothing in this implementation.
+	 */
+	protected onTransformed() {
+		// do nothing
+	}
 }