Aunt Will is the aunt of Captain Earwax and is played by Jan.
The very feminine Aunt Will
In episode 2 we see a younger Bruce Plain (Captain Earwax) living with his uncle Ken and aunt Will. In this episode we see Aunt May trying to put an apple in the toaster. Later she tells Bruce that his Uncle, her husband, is killed by the Joker.
Aunt Will is a joke reference to the character of Aunt May who appears in the Spiderman comics.