Can anyone tell me what key signature is used in the majority of Primus/Claypool songs? Also, is there a list that tells what each key sounds like in terms of tone (sad, bright, etc.)? Thanks.
not sure about key signatures, but they're awfully fond on using tritones, aka diminished 5th intervals
They play in all different keys, so as to give their music variety.

Major keys are uplifting, minor keys are darker, or "cooler"