Skip

Simon McCarthy "Skip" York is an extremely talented ghost who has the ability to shape-shift. He was killed by ghosts when he was on a ghost hunting assignment for Gariwald. As a ghost, he attempted to take revenge on Gariwald by taking over the Puffle Hotel and trapping him in his own machine, and then tricked you into capturing the Ghost Puffles. With the immense ghost energy he collected, he took on a destructive appearance, but was stopped by two of your well-aimed snowballs. He still retains his advanced ghost form, although it is severely weakened. With enough energy and focus, he is able to shift out of his physical form, transitioning into his ghostly form, where he is free to use his powers with ease.

Early life
Not much is known about Skip, but here is what we currently know thanks to Hunter9463:

Simon York was born on October 23rd, 1992. Due to his family's rough conditions, Simon was expected to provide money for his family alongside his father; after working for 4 unsuccessful jobs, he resorted to stealing from strangers. In his later teenage years, however, Simon became a ghost hunter and worked in a ghostbusting squad with Hunter; even then, he left the squad in June 2012 to hunt on his own. Alone and unskilled, Simon ran into trouble one night as he was on an assignment for Gariwald. Without anyone to help him, Simon was overrun by ghosts and killed, skipping away as he fled and earning his nickname.

Now a ghost, Skip became vengeful and wanted to take revenge of Gariwald for (indirectly) causing his death.

Puffle Hotel
Skip disguised himself as a bellhop in the Puffle Hotel as cover for his mischief in 2014. His plan involved tricking someone into capturing Ghost Puffles, then harnessing their powers to achieve a monstrous form. Unfortunately, for some reason there were quite a few problems with his plan, like the blatantly visible panel that unlocked the Ghost Puffles and Gariwald, cutting off his power source before he could fully absorb their ghostly energy. Regardless, Skip managed to escape, and pops up every once in a while to cause mayhem.

Trivia

 * Skip is able to fire immensely resistant ghost energy that acts as a wall to block a penguin.
 * Skip skipped school many times and graduated with relatively low grades, even though he is extremely clever.
 * Skip and Protobot, after both of their incidents in Club Penguin, were instantly ranked up on the EPF's Most Wanted list to #13 and #12 respectively, right behind Questisbak, whose rare but powerful invasions are devastating.
 * Some people speculate Skip and Protobot may work together.
 * Skip is able to easily survive severe attacks given to him, but there are multiple ways to eradicate him if need be.
 * Skip's favorite food is Macaroni & Cheese.
 * One of Skip's many talents is being able to easily fake a personality to his benefit.
 * Skip can speak fluent Russian.
 * Skip has skill in cooking, but rarely practices it.