Johnny Deepend

Johnny Deepend is the fourteenth boss encountered in Luigi's Mansion 3. He is a swimming instructor fought at the Fitness Center and holds the elevator button the grants access to The Dance Hall. His name is a pun on the "deep end" of a swimming pool and possibly on actor.

Appearance
Johnny is a muscular orange ghost with black hair that wears a green leotard, a striped swimming cap and a pair of swimming goggles.

Battle
Johnny mainly attacks by throwing polo balls, even when Luigi first enters his room. Since he immediately dives out of reach if Luigi activates the Poltergust G-00, Luigi has to send Gooigi through the fences around the pool to reach a wheel that will drain the water. If Gooigi is active, Johnny will attempt to dissolve him by spitting some of the water at him; while Gooigi can take cover behind the pillars around the room, he will be completely exposed while he drains the water. As such, Luigi can temporarily knock Johnny out by hitting him with one of his own polo balls, giving Gooigi time to get to the wheel and turn it with his vacuum.

Once the drain is opened, Luigi or Gooigi can descend into the now-drained pool to confront Johnny, who is now stuck in the open drain. At this point, the his only attack is to slam the ground with his fists; although this deals significant damage, it has limited range. Luigi (or Gooigi) needs to stun Johnny with another polo ball, allowing them to remove his swimming goggles; afterwards, he is finally vulnerable to being stunned and captured.

When his HP is depleted, Johnny makes some poses before pinching his nose and being sucked into the Poltergust, allowing Luigi to claim the elevator button. However, much like with Morty, he will have to deal with Polterkitty stealing the button when he goes to put it into the elevator.

Trivia

 * Johnny Deepend has the second-lowest HP of any boss ghost in Luigi's Mansion 3, with Morty having the lowest HP.