Electroids make their first appearances in "Memories of Boom Boom Mountain." There are at least six of
them shown, and they get into an argument with a toad. They accuse him of stealing their triangle, and the toad accuses the Electroids of stealing his plum. Finn eventually works out a plan so that the Electroids get their triangle back while returning the toad's plum. One of them is voiced by Matt L. Jones.
The Electroids are generally a shade of blue or gray. An Electroid's entire head and torso is combined and sphere-shaped. Their limb joints are marked by circles. Whether they have arms or legs varies.
That guy stole our triangle!