Kill the Mutant Giant Bats

Kill the Mutant Giant Bats was going to be a quest in Van Buren, the canceled Fallout 3 by Black Isle Studios.

Quick walkthrough
Mutant bats live in one of the Blackfoot caves, and are attacking the Blackfoots during the day.

The bats aren't a threat to you unless you're a ghoul (they'd rather eat fruit and bugs), but you can decide to kill them off anyway. If you kill them off, then manti swarms become possible random encounters near the town, and the float text of the Blackfoots in town mention the increased number of mantis from time to time.

CombatBoy
Kills!

ScienceBoy
Can poison them!

DiploBoy
Can talk some younger tribals to help him kill the relatively harmless giant bats!

Stealthboy
Can sneak about the bat lair during the day and is less likely to wake them all up when murdering sleeping bats!

Normal Journal
Mutant bats live in one of the Blackfoot caves. If they were wiped out, the Blackfoots would have another cave they could use, assuming they cleaned up all the bat shit.
 * I've killed some of the mutant bats.
 * I killed all of the mutant bats in the Blackfoot caves.
 * I've overheard the Blackfoots talking about the greater numbers of mantis roaming around the wasteland ever since I killed off the bats. Maybe the bats were eating the mantis.

Dumb Journal
Bats in Blackfoot caves. If kill bats, Blackfoots have nice new cave!
 * Me killing the bats.
 * Me killed all the bats in Blackfoot cave.
 * Blackfoots say many more mantis in the wasteland this season.