This is my absolute fav glitch in New Vegas. Might work in Fallout 3 also.
Shoot a companion, or any essential creature in the head, rendering them 'unconscious'.
Then, wait til they start to resurrect, and go into bullet-time or vats, and get another killshot on them before they resume their standing position. The results are hilarious, and rather unstable. Sometimes they end up looking like they just got whacked by a giant from Skyrim. Essentially, they become satellites.
Try it out!!