A splinter in the ass,usually done while moving from a sitting position on wood or wood-like materials. A splass is very irritating and will hurt if rubbed against.
Me:Today i was trying to scootch over on the bleachers during gym and in the process, I GOT A SPLASS!
Them:A what?!
Me:A SPLINTER IN MY ASS!!!
Basically means extremely powerful, dangerous, high leveled, or possibly even feared. It's used as a rank to describe the highest you can possibly achieve. It's pretty commonly used in anime.
what mr. ramsey's class is in simple terms is hell. He makes your life hell. his class is the most boring of them alll. He has the most stupid rules and is cringey af. he is getting on my last nerve.