condensation, when things that are cold heat up it makes condensation, which is just water, water vapor doesn't mix with oil so it makes that milkshake looking crap. pretty normal on almost everything. It's bad if all your oil looks like that. If you pull the dipstick and the oil look clean, and the coolant is still normal color you haven't a thing to worry about.
Originally Posted by Los
^He's been drinking beer and destroying pumpkins with brake rotors and sledge hammers.
So, pretty much just doing man stuff.