MAMMATUS is a playable word

mammatus Scrabble® Dictionary

noun
pl. mammati
a type of cloud
62 Playable Words can be made from "MAMMATUS"
   2-Letter Words (11 found)
   3-Letter Words (22 found)
   5-Letter Words (7 found)
   6-Letter Words (1 found)
   8-Letter Words (1 found)