The mind connector was built out of two pink pieces resembling a sink plunger's rubber cap, which were stuck to a reddish-brown cable. If one button is pressed, the pink cap attached to the operator's head completely wraps around them, making them look like a hot dog wiener.
The end of the connector is put on the brain or heart of somebody, and the other end is stuck to the head of the other person. But when Plankton puts this cable on SpongeBob's heart and the other end of his head, he then morphs into SpongeBob. The same transformation goes for Patrick.
Role in episode
Plankton accidentally flies into SpongeBob's head. He then uplugs SpongeBob's eyes and inserts his mind connector into the power outlet. This causes SpongeBob's eyesight to be lost. Plankton is excited to see how a Krabby Patty is made, only to be disappointed when SpongeBob's lost eyesight causes him to make a patty made out of cleaning utensils.
Plankton then goes for SpongeBob's ears, uplugs them, and inserts his mind connector into the power outlet to hear Mr. Krabs reveal the formula. However, due to SpongeBob's sudden loss of hearing, Mr. Krabs is forced to repeat himself several times until using a megaphone, which affects Plankton's hearing.
Plankton then puts the mind connector on SpongeBob's heart and transforms into SpongeBob.
After exiting SpongeBob, Plankton, with his mind connector still on, is flung onto Patrick and then transforms into the latter as a result.