Crazy Dave is your neighbor in Plants Vs. Zombies
, who gives you hints and sells you useful items to fight the hordes of undead trying to break into your house. He wears a pan on his head to protect his from zombies. He also appears to like tacos, even willing to pay $1000 for one.
On the brains second playthrough of the adventure mode, Crazy Dave will pick three plants for you on each level, making the game harder as his picks might be (and often are) useless.
Aside from the upgrades he sells, the trunk of his car also includes a copy of "War and Peas" and has the mascot of PopCap
game in there as well. He used to be called the Fogman because he... well... wouldn't want to spoil it for you.
Crazy Dave makes a cameo of sorts in the The Passing campaign of Left for Dead 2, with a wall which has "Looking for an M60? come see me - Crazy Dave" written on it.