Monster Manual, Flame Skull, Typo "Cantrip" s/b "Cantrips"
This monster was the other one where I couldn't delete the spells, drop it on the combat tracker and have its single Cantrip, mage hand, parse out. I finally realized its because the Spellcasting trait says "Cantrip (at will): mage hand" instead of "Cantrips (at will): mage hand". The parser wants plural not singular even it it is just one cantrip. :p
That one got to me, I knew it had to be a typo or extra character but I just couldn't see it for a while, LOL. Now it's all yours.