Hitmonleet imma give you one. This is my first one, so tell me if it stinks. XD
CoolStoryBrobat the Zubat. (if the name doesn't fit, type CoolStory or something along those lines.)
Now, this Zubat heard how you had a ghastly with a Smogon addiction, and sees this as a personal challenge. As Haunter gets stronger, Zubat realizes that he too must impersonate a Smogon official as well. He however wants to pose as a fair challenge for Haunter, so he impersonates him in many ways as well. After defeating other haunters, he realizes that he does not have as much enmity for Haunter than he thought, and makes up for his past aggressiveness by supporting Haunter in all of his future endeavors, even putting his life on the line. However, now that he is fiercely loyal to Haunter, he must protect Haunter from all of the impostors.
To summarize:
-Must catch CoolStory after Haunter.
-Must stay within 5 levels of Haunter, so as to pose a fair challenge.
-To also pose a fair challenge, he must have the same amount of physical, special, and status moves as Haunter.
-Must solo Morty's other Haunter to evolve.
-Unless it interferes with Haunter's rules, CoolStory must "protect" Haunter from all other ghost types and solo them (after Morty).
-If Haunter's number is under 75, you can sacrifice CoolStory to keep him.
-Must solo Karen's Gengar to evolve to Crobat