Merman, a Sea Morphing mob.

- Oceans are a bit lacking in terms of hostile mobs. And Merman could fill that a bit. Merman is a neutral mob found in all deep variants of ocean biomes that can morph into different aquatic mob except Axolotls, Guardians and Elder Guardians.

- Their behavior is tricky, if they are disguising an aquatic mob and found a player that don't care about them, they will follow them sneakily. If a player kill them, they will morph into their real form, a Merman and will attack you.

- If the mob that Merman was disguising as, has a trident, they can use it as a ranged weapon. If there's nothing, they will try to sink you if you are 8 blocks near him. If you hit them, they will swim away from you just like Guardians.

- If they were spawned in land, nether, or end, they will flop around in their real form. If they can find a nearest water they will try to go there and disguise as a mob that can reach his sight.

- If you managed to kill them, they will drop 1-3 Merman Flukes and can be used to brew the "Potion of Mischief". If you drink this, you will turn randomly in three mobs: Pufferfish(50% chance), Drowned(20% chance) and Axolotls(30% chance) for a short period of time. Their properties can be shared to you. The potion has duration, minimum of 50 seconds up to 1 minute and 40 seconds.