Johnny Deepend

Johnny Deepend is the fourteenth boss encountered in Luigi's Mansion 3, who haunts the Fitness Center and guards the fourteenth floor elevator button.

Appearance
When Luigi enters the pool area, he assaults Luigi with volleyballs.

After Gooigi drains the pool, Johnny Deepend will struggle to evade being sucked down the drain as its draining, to no avail, and is stuck inside.

Battle
Johnny Deepend frequently assaults the player with volleyballs. Luigi has to distract him while Gooigi goes over to the drain lever to drain the pool though he can squirt out water to dissolve Gooigi. The player can knock him out by hitting him with one of his Volleyballs during this time which will buy Gooigi time to get to the drain.

Afterwards, the player, either as Luigi or Gooigi, can descend into the now drained pool and then hit Johnny Deepend with any volleyballs to knock his goggles off, stunning him long enough to suck him up. Otherwhise, the ghost's only attack is to slam the ground with his fists. Upon being sucked up, he'll do some body poses before allowing himself to be sucked up, with Luigi getting the fourteenth floor button.

However, much like with Morty, Polterkitty will swipe the elevator button when Luigi goes to put it back in the first time.