Monster Cat

Monster Cat is the former Instant Villain from Vigilante - My Hero Academia: Illegals.

Appearance
Its appearance is identical to that of a normal cat.

After activating its Quirk by the effects of the Trigger, Monster Cat merged with the transport having two tails and the complete appearance of the transport with its face below the glass.

Personality
Once he was under the effects of the Trigger, Monster Cat became violent and erratic.

Abilities
High Speed: Monster Cat is quite fast thanks to the merger with transport.

Quirk
Monster Cat: Monster Cat's Quirk allows it to fuse with an object of its choosing, becoming a cat-object hybrid. It can also defuse from said object.

Trivia

 * Its merged form might be based on Catbus from My Neighbour Totoro.
 * This is the second known case of an animal gaining a quirk, the first being Nezu.