Re: "Mostly Harmless" powers
It wasn't Champions, but in another game I was involved in I wrote up an NPC who could alter the temperature of anything he touched. I suppose superhero jargon would call it tactile thermal kinesis. A nice side effect was that he was immune to frostbite, being burned, and any other effects of extreme heat or cold.
In theory it could make a useful attack power, but this character went to school and became a chef. Why wait for the pot to boil when you can just put your hand on the side and speed up the process?