The Radroach is one of the weakest creatures in the Capital Wasteland. You first encounter them in Vault 101, and you have to kill one with a BB Gun in the Growing Up Fast quest. Like many places Vault 101 is crawling with them, due to an infestation.
They're very easy to kill, and Followers normally don't treat them as a threat, and ignore them (even though the red tick mark is on your compass).
- Main Article: Escape!
Butch's mom is trapped inside a room filled with Radroach's in the quest. You can choose to save her (yields good karma), convince Butch to overcome his fear of the roach's and kill them (also yields good karma), or ignore the request.
- The Radroach is very similar to the Mudcrab in Bethesda's Elder Scrolls IV: Oblivion when it comes to strength.