Steam

Steam burns really hurt.

Little lunch-time microwaving situation involving steam and a burn on my finger.
...
It's amazing really. I have a little blister line maybe half an inch long on my middle finger. I've had it in water off and on. Have to work though. Sometimes it is fine, other times it hurts as soon as I take it out of the water. Pretty amazing really.

Not nice though. Wouldn't want to suffer a serious burn, can't imagine that...