Phineas and Ferb (2007)

S02E19 Hide and Seek

Phineas and Ferb decide to spice things up by turning their indoor hide-and-seek game into an adventure, shrinking down their friends, including their enthusiastic new fan, Irving. At the same time, Dr. Doofenshmirtz has a sneaky plan of his own—he attaches a nanobot to Perry in hopes of uncovering the secret of where the clever platypus resides.