|This article does not cite any sources. (May 2020)|
The Drones were flying B.O.W.s that resided in the part of U-8's abdomen originally intended for the maturation of eggs in an unaltered specimen. These flying B.O.W.s are not larval U-8s, but completely different creatures entirely.
It appears the drones are designed to replenish ammunition and hand grenade supplies more than its intent to be a challenge.