I love the Darumaka droppings, that's hilarious. Boiling someone's drink would be funny, or at least making it lukewarm so they drink it and go "eeuuurgh, what is this?!" Hot metal, sounds like something they'd do to me at work :P (Also no big deal Zoro, I'm just glad you didn't disappear for good :P )
EDIT: Superstrength ninja'd me :P That's a really good one, especially for those who work at 4, 5am and get up when it's always pitch black. Rush around and then see the clock. "ALLLLLVIIIIIIIIIN!"