Pumpty is a large red-violet robot with an all-around glass encasing center. It has large construction digging claws for arms and feet and one large green eye on its top.
New World Saga
Eggman used Pumpty to hold Amy, Tails and Christopher Thorndyke hostage inside its glass case while Sonic the Hedgehog fought Knuckles the Echidna over a dispute concerning how they were all sent to the human world. Eggman had simply tricked Knuckles by claiming he wished to be good and that it was Sonic's fault. Tails manages to unscrew the hatch leading into the robot's mainframe system but Amy persists and smashes it with her Piko Piko Hammer, causing a part of the glass case to shatter. However, when Knuckles failed to eliminate Sonic quick enough to satisfy Eggman's tastes he set Pumpty on the other side of a lake and claimed that Sonic couldn't save them because he couldn't swim. Sonic proves him wrong by running around the lake and taking out Pumpty's legs, setting his friends free.
Knuckles realizes that Eggman had been lying to him and he joins up with Sonic to take out the robot. He punches holes in its body then smashes its head, breaking it in two down the body. Afterwards, he sends Eggman flying with a punch.