Rogue Spider Mite?

I found a single spider mite webbing a freshly rooted clone today. I just brought the clone in from another room yesterday where the humid is at 80%. First off I didn't think spider mites could live in high humidity and second, is there such thing as a single spider mite? I inspected the shit out all my plants and no spider mites to be found, just the one.... Should I do something other than kill the single adult?

KILL IT!!!!!!! dip ur clones in a solution ( neem, dishsoap, ect) and watch carfully as it mite not kill all the eggs! I HATE MITES!!!!!!!! good luck!