Cats do a lot of weird things. And I mean a lot. So the fact that this one is up there in the top five weirdest, really means something. If you have two cats (or more) that like wrestling with each other, you know they can get pretty intense, and throw down hardcore. Not too weird; they are relatives of some high-class predators, after all. But what is weird is that in the middle of their all-out brawls, they'll simultaneously and instantaneously stop for a cleaning break.
Think about it, you're knocking some punk around for giving you a regular coffee when you clearly asked for half-caff, or whatever it is that gets you into fights with Starbucks employees, when he yells, "Hold up, can we clean our nails for a minute? I really need a manicure. I promise we'll box this this out in five, but the dirt under my thumb is really bugging me." And you're all like, "Sure thing. That's a great idea. You know what? Why don't I clean it for you? Here, give me your hand, I'll get that dirt out." And he's all like, "Thanks, that's so kind of you," and then 20 seconds later, after the dirt's gone, Bam! you smack him in the head as hard as you can, knock him to the ground, and start bunny kicking him.
Cats, you really are weird.
(flickr photo Taking Catre of Each Other by Martin Staviar; http://www.flickr.com/photos/12073313@N04/2768305793/)