Okay so just as a heads up for this, I probably should make this clear: 

I wanted to make this more as a crossover short film, since both the Pumpkin Rabbit and the Grabber mostly just chill in their house. The only plausible way I could think of that would actually get them fully motivated to kill each other is when they end up interfering with each other's business in a gruesome manner! 

  
As for who wins, I genuinely don't really know and I'm leaning on it being a stalemate until I'm convinced otherwise. Limiting it to just their living selves, it could go either way. The Pumpkin Rabbit clearly has superior overall stats due to his height dwarfing the Grabber and his feats of strength being greater than the Grabber's, while the Grabber's superior arsenal would definitely trip up the Pumpkin Rabbit and would still land very serious wounds. I intentionally left out the spirit version of them because then that would make their deaths VERY specific in how it can be executed, and I just don't see them getting the one-up on each other for a long time. 

I'll post my take on the verdict in about a week as I'm still busy with other projects.

Tales of the Black Phone - Mysterious House x Black Phone Crossover Rough Draft