When you overheat yeast the yeast should turn a bit darker and when you check it with your cursor it says "DYST" which i cannot find in the powder toy list of things you can use. Oh and just in case this might help when you overheat DYST you get DUST which is in the powder toy list of things.
Dead Yeast, get it by overheating or overcooling normal Yeast. At first it was glitched to automatically die, now it's fixed. Check Other Topics before Making Your Own! //Dust is the next Stage of dead Yeast.