Once per turn: You can toss a coin and call it. If you call it right, destroy all monsters your opponent controls. If you call it wrong, destroy as many monsters you control as possible, and if you do, you take damage equal to half the total ATK those destroyed monsters had on the field.
Not me, but I dueled someone using three of these. Aside from the fact that I won, this person had to be the luckiest duelist I've ever faced. He got 3 Defense Draws on his first turn, then got the time roulette in his favor 3 times in row (no second coin toss or luck skills) to kill my monsters. He kept bringing it back with Magical Exemplar and using Magicians Unite. I thought I was gonna die...
I'd throw Destruction Jammer in my Mind-Controlled Joey deck if I had it, just because I'm so annoyed by this card.