Dr hax

[sMaSh]

Ha ha ah ahahahaah this is prob what rage looks like irl

[sMaSh]

There are other videos with this kind of mod on you tube funny stuff

[Variasaber]

There are other videos with this kind of mod on you tube funny stuff

Yup, it's a standalone game called Garry's Mod, it lets you mess around with objects and ragdolls and weapons and stuff in the Source engine. Very fun. The Dr. Hax ones come from a series called the GMod Idiot Box, which is one of the better GMod comedy series on YouTube... most of the stuff you'll find is garbage, but GMod Idiot Box is pretty good.