The Garfield Show (2009)

S02E15 Dogs Day

After Odie assists their friend Nimbus, the space alien, Nimbus rewards him with an everlasting doggie cookie. Following his treat, Odie gives Jon a playful lick, causing Jon to suddenly behave like a dog. In a surprising twist, Jon then licks Liz, leading to the same canine antics spreading to her as well.