Hard to choose, they are all great in their own way.
I guess “The Deadly Mantis” because of the “little man in the boat” joke that has changed meaning in adulthood from when I saw it as a child. Eegah and Manos do stand as cornerstones, but Mantis has that one line that is burned into my association with the show and holds a special memory.
Severe brain damage; to such degree that having the desire, or enjoyment of music, impossible.
I would rather be a vegetable than give up Baby Shark.