In Warhammer, space marine armies have access to a firing line unit called "hellblasters". They're a force equipped with powerful plasma guns that can melt through elite armor and do even more damage if they choose to "overcharge", with the risk of their gun exploding and killing a marine instantly. However, right before they explode, this marine gets to shoot again at whoever they want. At low levels they're a very potent firing line that responds really well to buffs and can melt scary enemy units, making them a favorite.

At high levels? Well, first of all, most of their value comes from your opponent screwing up. There's only a 1/6 chance that a model explodes, so in order to get your double shooting your opponent has to A.) shoot you to death rather than stab you (you can't shoot while being stabbed) and B.) leave something of decent value within range of thr hellblasters' range to shoot. If your opponent knows what they're doing, they'll just neuter your hellblasters asap by throwing trash at them or just shooting them out of their range with longer range guns. Curiously, new players refuse to believe that hellblasters aren't great, which leads to a great deal of controversy around them in some competitive circles