See linked youtube. Not the first time I've seen it. If you go up close, the shanks little fans are still animating too. Sorry I should clarify, this appears to only happen when you create a firefly explosion near a shank, which kills it. Shanks explode when they die regardless of how they are killed. Edit: I know shanks don't have critical spots. I'm talking about indirect damage from firefly explosions on other mobs.