I spawned a houndeye from HL1 in GMod, it shocked me or whatever it does, then there was some fuzzy/static noise, it shocked me again, and then a clock with a sad face popped up, after the clock disappeared, there was some random high and deep voices playing all at the same time, I think they were from HL1?
Where did you get the mod from?
What mod? You can use HL1: Source models and NPCs in GMod
Reinstall the game