How about a diminishing returns for PKing the same person multiple times? Like, if you kill someone twice, you won't get credit for killing them again over the next 3 minutes (give or take)? That would stop players from "boosting" from most mob PKing.
But as far as getting PKs from the giant blob, who cares? It doesn't spawn that often. If some people want to take advantage and rake in some PKs, that's just being smart. The fact that some people have a problem with it is a joke. I mean, seriously?
In regard to the people wanting the yeti to be a "guild boss" of sorts, that's not what I was going for. Something like that definitely could be implemented, but this isn't what I intended for this particular enemy. But I am starting to think that it shouldn't have any rare drops, and solely drop tokens, with a small chance of dropping 2. This means people won't have to rely on luck. The more you participate in killing it, the more tokens the get, the better items you eventually get to purchase. However, I still think there should be one incredibly rare possible drop, just so you can have that moment of anticipation when you open the spoils.
Now, back to the "PK boosting". If people really think that's a problem, they could turn PK off in the area it spawns (though still no walking through eachother). However, I don't think it's necessary.