"le plus mal and le pire"

Question

When ı had a look at the irregular adverbs forms I saw that the irregular form of "le plus mal" was "le pire"
isn't it incorrect? Because when I investigated it I saw that it must be "Le pis"

C'est lui qui danse le plus mal He's the one who dances the worst. (I think this is correct)
C'est lui qui danse le pis He's the one who dances the worst. (I think this is correct)

C'est lui qui danse le pire He's the one who dances the worst. (I think this must be incorrect)

Am I wrong?
please help

Accepted Answer

Hi Ozan,
You can only say correctly -
C'est lui qui danse le plus mal 
You might say -
C'est le pire danseur que je connaisse = He is the worst dancer I know
'Pis' is little used, except in the expressions -
tant pis! = never mind!
ça va de mal en pis = It is going from worse to worse
I hope this helps!