I think this was on an episode of Buffy...

Alien Iguanas Fall From Florida Trees During Cold Snap

Alien Iguanas. Seriously, now? Iguana aliens? Color-changing lizards from outer space? Dropping on people's heads? They are just making things up.

(Okay, yeah, whatever "alien" in the sense that they are non-native species to this area of Florida.)

This, unlike other National Geographic Portends of DOOM^TM, does not at first seem to foretell mass death and destruction, but Constant Vigilance! people. While reading this story, I began picturing little alien iguanas in little iguana space suits with little iguana bubble helmets and began giggling and almost choked on a peanut. Whatever evil forces are behind the NGPOD^TM, are getting sneakier. . .