Puppet SpongeBob

In the leadup to the theatrical premiere of Jimmy Neutron: Boy Genius in 2001, Nickelodeon featured several pop-ups in which Jimmy used his gadgets to mess with various shows on the channel. In this one, shown during a re-run of the SpongeBob SquarePants episode "Hooky", Jimmy temporarily turns the show's cast into felt puppets.

Example of:
Medium-Shift Gag