Sometimes an enemy being defeated just... explodes. Not metaphorically like in the Villainous Breakdown sense, but in a literal, physical explosion. In the case of robots, this could be justified, as the defeat would probably cause them to short circuit and the spark to ignite their fuel. But this is not limited to robots, since this happens with characters who are not specifically stated to be robots, and in some cases are implied to be organic in some way or another. See also Explosive Overclocking, Chain-Reaction Destruction and Load-Bearing Boss. Subtrope of Made of Explodium.