Squeaker is very small and short. He is a grey robotic mouse with blue eyes, a skinny tail, and slightly large ears. His eyes turn from cute to aggressive when he sees Bolts. He has the ability to curl up into a ball. He used to have the ability to explode.
Before he was reprogrammed, he showed and uncontrollable aggression towards the Thunderbolts. Now, he is sweet and mellow towards them (except Bolts). He shows much care towards Blip, as he is Squeaker's owner.