Enemies explode into even more enemies

[Thomas Foolery]

I find myself getting swarmed by multiple enemies, so I use a Crash Attack to knock them away. As it turns out, they can bounce into each other and deal damage to one another that way. However, when I do this, they become even more lesser enemies. Is this a bug?

[Netsa]

Nope, Bonus Ninjas. They have a higher chance of showing up if you're doing well.