Icetromper

ASK FANTASY FLIGHT 

Q: Is it possible for the Icetromper to target itself with its effect when attacking in order to get the effect of a sacrifice?

A: Yes. The Icetromper there is a valid target unit at the time you initiate its ability. Once initiated, the cost is paid (sacrifice), and by the time you would fulfill the effect, the target has left play, so nothing happens.