A large shit that makes a nuclear explosion of biblical proportions causing vaporizing of all matter within 200 yds following the pinching off a monstrous turd.
Detective: Why is this house vaporized, Fire Chief?
Fire Chief: Well sir, it looks like we have another case of an Atomic Shit this week.
Detective: I suspect someone within the household visited a spicy, Mexican restaurant within the past 24 hours.
When one hangs from the top of a restroom stall over the toilet and deficates, releasing a death bomb of fecal matter that creates a title wave physically impossible to contain in even the best toilets.
The Atomic Shit is every school janitor's worst enemy.