Codename: Kids Next Door (2002)

S2E12 Operation: K.I.S.S.

Numbuh 2 experiences a classic transformation reminiscent of Dr. Jekyll and Mr. Hyde when his experiment to enhance hamsters unexpectedly turns him into a teenager—and back again! After being kicked out of the treehouse by his oblivious teammates, he unexpectedly finds comfort in the company of Numbuh 5's wicked sister, Cree, who ends up developing a crush on him!