Phantamanta

Phantamanta is a boss in Super Mario Sunshine and is also the cause of the disappearance of Hotel Delfino. It appears in the first episode of Sirena Beach, "The Manta Storm". It is a pale pink silhouette of a manta ray. When hit by water from F.L.U.D.D, it splits into smaller versions of itself. It possesses the uncanny ability to project itself over any surface of varying elevations instantaneously, much like a shadow.

Wherever Phantamanta moves, it leaves a trail of blue and yellow electric goop. However, Mario can spray the goop with F.L.U.D.D. If there is even a tiny drop of it left, Mario can get shocked when he touches it. The only area where the Phantamanta cannot reach Mario is if Mario is under one of two huts. The Manta first divides into two. Each of those Mantas can divide into two more. Each of those divide into four Mantas. And, each of those can further divide into four more Mantas, making a total of 64 Mantas to defeat. When all of the Mantas have divided fully, they will turn red with anger and start swarming towards Mario. Once the last one is vanquished, Hotel Delfino will be restored, revealing a Shine Sprite for Mario to collect.

Trivia

 * Phantamanta's music is a remix to the normal Boss music.
 * In Mario Golf: Toadstool Tour, one of the default names on the scoreboards is Phantamanta. One has to imagine how Phantamantas can possibly play golf, since they are only silhouettes.
 * The 64 Mantas the player has to defeat may actually be a reference to Super Mario 64.
 * The largest form of Phantamanta actually does pursue Mario, even though it is not coloured red.
 * Phantamanta's name is a pun on the words "phantom" and "manta".