At Disneyland I hid in some rock cave thingie on Tom Sawyer's island and freaked little kids out by grabbing their arm or going "rawr!"..... I'm obnoxious.
i have this whistle on my keychain, and at inappropriate times, I blow it at full force and it sounds like what a dog hears when you blow a dog whistle.
I'm just generally a sarcastic smart-ass to people most of the time. That can get pretty annoying. I've learned to tone it down a lot though, for reasons of self-preservation. "I shouldn't do it if it's not conducive to a long life..."