Peekaboo!

Disguises are applied with the /peekaboo command. It can disguise the source entity as a specified entity type, optionally with an additional entity, or disguise a player with the skin of a named player. A disguised player looks like the chosen mob, for example a pig with the player's name tag still showing. The command can also replace the source entity's custom name with a text component, set a scale modifier, toggle whether the entity casts a shadow, and clear the applied disguise properties.

The mod also adds an equippable head slot item that replaces the wearer's player model with a disguise item, and a Mob Hat style item that shows an entity model on the head. Disguises work on living entities generally, including entities with AI, players and armor stands. Use is currently limited to creative mode. Installation requires NeoForge only. The environment is client and server, so the server and every player need the mod, and it is released under the Mozilla Public License 2.0, so the source code is open source.