I have to agree with most everyone here that Silent Hill 2 probably causes more brix to be shat per-minute than any other game. The whole thing is a giant Shat Brix Generator.
The Ocean View Hotel mission in Vampire the Masquerade: Bloodlines is somewhat-famous for causing extremely projectile brix-shatting. That game also has a series of missions involving an abandoned hospital that is pretty creepy just because of what it is (and because it reminds one of Silent Hill 2), and because it is inhabited by a certain cannibal who doesn't act like you'd expect her to. Which is a lot worse than if she'd just attack you.
I also nominate the now-infamous Deadly Premonition. Brix are not necessarily shat from fear because of this game (though it rips off Silent Hill enough that it might do that for you), but it certainly has the most WTF moments of any game I've played (some intentional, most accidental, all hilarious, confusing, irritating and perfect at the same time.)