In the Ghost Zone a young half ghost was flying towards the icy islands that form the Far Frozen. The halfa was worried, just a week ago he began to feel strange vibrations coming from his core, it wasn't painful and it only happened when he was relaxed for some unknown reason. Not knowing what else to do Danny decided to visit his yeti friends, after all they were his official ghost doctors.
"Great one!" the leader of the Far Frozen received him as usual, with a literal bear hug.
"Hi Frostbite" Danny hugged back.
"What brings you to our humble home, Great One?" Frostbite asked.
"Can't I just come to visit a friend? Also what's with the humble home thing? You guys are the most technologically advanced society on this side, as far as I know" Danny said.
"Ha ha ha! Of course you can come visit" Frostbite said letting him perch in his shoulder while pretending to not having heard the second part of the sentence, "but you don't usually do"
"Heh, that's true I did come to visit, but also to be checked over" Danny said while rubbing the back of his neck.
"Oh? Is there something wrong?" Frostbite asked worriedly.
"I don't know" Danny said.
"Alright we'll go to the medical facilities first then we'll talk" Frostbite said.
Once in there Danny described Frostbite the weird sensation in his core.
"… and I don't know why it happens or if I should be worried about it" Danny ended his explanation.
"I see. Great One there is nothing to worry about" Frostbite smiled at his young friend.
"Really?" Danny asked.
"Yes, that vibration only happens when a ghost is in a safe place and feeling content" Frostbite said, "its commonly called core purring"
"Purring. Like a cat?" Danny asked.
"Exactly" Frostbite nodded.
"Great, now I'm a cat" Danny said sarcastically, not noticing his core started to vibrate. He should have expected the feast Frostbite throw in joy of him purring at his side.