ViolentRoses

ViolentRoses ("VR") allows the user to Morph into any creature and unlock their abilities.

When you initially join a world with VR, you will be prompted to click a message in chat. This message will decide how you unlock your morphs: Kill to Unlock or Auto-Unlock All.

When morphed, your entity data is changed to represent as the entity you are morphed as (unlike other mods where you only become invisible and they teleport and anchor a entity to you). Death messages when you kill someone while morphed don't show your username and your nametag is hidden when morphed. So, instead of "Player was slain by GumPaper," you get "Player was slain by Zombie."

To use a Morph's ability, simply press the ] key. Certain mobs are handled differently than others, though most drain two hunger per ability-use.

An example of those handled differently is the Vex mob: it's phase ability allows the player to phase through blocks (by holding the trigger key) but it constantly drains (one hunger bar every two seconds) unlike a Blaze where shooting a single fire blast costs two bars.

You can morph by using the /morph minecraft:id command. This command also works for modded entities, but if they have custom abilities, you very likely won't be able to use them, as I (or the mod's developer) need to hand-code compatability.

You can also set your unlock-method for morphs at any time (as an op) using /morph unlockmode all/kill. Additionally, you can optionally turn off ability costs using /morph abilitycost true/false.

Note: It is suggested  not to use ViolentRoses with mods that both add health bars and show entity names above said healthbar, because it will likely show your username. Any other mods that try to read NBT/player data directly may also conflict. Thanks for your time!