I’ve just been watching a bunch of YouTube video reviews of forthcoming Ninjago Season 14/spring 2021 sets. The main antagonist is called Chief Mammatus. All of the videos I have seen so far mispronounce his name.
Mammatus is an existing word in English. It refers to a kind of pendulous, bulbous cloud formation. It’s pronounced mah-MAY-tus, not MAM-atus or mah-MAH-tus. It’s possible that the Ninjago cartoon will mispronounce it as well which would be unfortunate.
Here is the minifigure as photographed by Brickset: