In the Belly of the Grandpa

In the Belly of the Grandpa is a three part season 2 episode of Ben 10, 2016 series.

Part one
Ben, Gwen and Grandpa Max meet up with Starshine who is now studying in inventing and has build something that she calls "the Mini-Size-O-Tron, a machine that can shrink any large object to microbic size. Grandpa Max gets poisoned by a strange parasite and goes a little cuckoo. So Ben turns into Grey Matter and journeys inside Max to find the creature while Gwen and Starshine help support him from outside and keep an eye on Max's condition. Ben runs into quite some trouble along the way.