Panty Soiling Surprises
The Mothership Zeta add-on for Fallout 3 was pretty much a completely different game. Rightfully so, since you are abducted by aliens and taken aboard their spaceship. I liked it for what it was, and having your character waking up on a table surrounded by little green men doing experiments on you was certainly entertaining (and funny, from my own point of view).
Probably the most surprising part of this was how fucking lost I got on the ship. Seriously, I don’t know who designed it, but they obviously were on crack. Apart from that, the only other thing to note here is how much the abominations scared the crap out of me the first time I came across one. That was a pleasant surprise in this otherwise boring add-on pack. The sounds those things make just creeps me the hell out, and for some reason their model doesn’t make me feel any better about them either.