User is a mouse demon

Pros:
-user is tied to targets and influence them
-user can shape shift into mouse or demon form
-user has super speed and enhanced small/hearing
-user can blend demon and mouse form
-user can change form freely
-user can adapt to quirk of target
-user can control target when in animal form

Cons:
-user is in pain away from target
-user will be more comfortable in animal form
-user will show unwanted emotions of target
-user can't hold blended form when bored
-user doesn't know control over target's quirk quickly
-user can only control target in animal form
-user will be out of control away from targets

Weakness: no target
User is "mildly bored" without a target