This is the only power in this game I still haven't figured out. You click it next to a guy, his body inflates, he screams a little and then he's fine. If I click a whole lot he eventually explodes, but the amount of clicks it requires seems to be random. Also, sometimes enemies near it inflate too, and only rarely they also die.

What am I doing wrong?

Clicking? I remember just holding the button down over them. Other than that you've figured it out. =)