Known to be an “extremely useful tool,” try it on vocals, organ, drums and, of course, guitar.
THC is not a full guitar amp modeling suite; it's a distortion pedal, pure and simple. But just for the fun of it, these audio samples demonstrate that a reasonable amped guitar tone can also be achieved with some additional EQ and compression. These were processed through THC, Digi EQ3, Tape-Head, and CT4. Grab the sample Pro Tools session here.