Green is not good at playing the trumpet. Trumpets are another thing that these guys shouldn’t be able to play, only having a mysteriuos black line as a hand with no fingers to press the valves.

Sometimes I draw the characters with side-mouths without the actual mouth line, just using the outline to show where the mouth is. I think this is supposed to be them pursing their lips, here to show surprise. Not that they actually have lips.