Grim Adventures Of Billy And Mandy (the) Easter Egg - Multi-Egg Episode

In the episode Herbicidal Maniac, where Skarr turns into a green plant thing, there are several eggs.

1) First and most obvious, you'll notice Skarr looks like a Pikmen from the gamecube games. He later mentions "budding" where his leaf turns into a flower. In the game, if your pikmen were given necter, their leaves would bud.

2)Right after the title of the episode, Skarr is waiting for a cow outside an out house. This is Cow, from Cow and Chicken, the old cartoon on cartoon network.

3) Finally, towards the end at the party, Pud'n yells that there is a candy bar in the pool. This is from Caddyshack, where some girl throws a candy bar into the pool and everyone freaks out because they think its crap.