After reading this
"In Dance Dance Revolution: Mario Mix, Waluigi's song is called "Destruction Dance". The song is a remix of the bonus game tune from the 1984 NES game Wrecking Crew, though the game itself did not feature Waluigi. Waluigi's special ball in Mario Superstar Baseball, the Liar Ball, splits up into a fake ball and a real ball. The fake one is an eggplant, again possibly referring to Wrecking Crew, because that had Eggplant Men as enemies. Also, in Challenge Mode of Mario Superstar Baseball, Waluigi must first obtain an eggplant before he can use this move. This also hints that the eggplant is Waluigi favorite food. Another thing in this game is the team logo for Waluigi Flankers - On it, Waluigi is wearing shades, and has a laugh just like Foreman Spike's laugh in Wrecking Crew '98. Also, In Mario Kart DS Waluigi's default kart was the Gold Mantis, a construction site crane."
(From Wikipedia)
I actually think that Waluigi may actually be Foreman Spike. I know it sounds stupid but that's just what I think.