The description & the flavour of the ability suggests it only works on frozen=stunned enemies.
However the player can attack the non-frozen enemies too.
Uncanny Snowman - 6
AP
(Build a Snowman) Bobby stuns the target for 2 turns and places a 4-turn Countdown tile. While this tile is on the board, this power becomes Punch a Snowman
(Punch a Snowman) Iceman deals 457 damage. Destroys all of Iceman’s Countdown tiles.
It actually looks fine, only pre-requisite for the punch is that the CD tile is in play.
Actually, in game (on iOS), it says “Iceman slides knuckle-first into the frozen enemy. Hitting them right in their carrot nose.” So, worded incorrectly. I’m fine with it since the in game discription is much more fun than the one you pasted 
I just don’t want to see the ability nerfed so that it matches the discription.