Finn was really Shoko’s tiger.
Think about it, how can you haunt yourself? Shoko just wanted her pet to give back the amulet. Plus they both tried to run away from her when they first saw her new form. Also tiger finn would be cool.
I couldn't help but notice that the relationship between Shoko and her tiger is very similar to that of Finn and Jake. Is it possible that, just like Finn is the reincarnation of Shoko, Jake is the reincarnation of her tiger?
We doubt that Jake was the reincarnation of the tiger due to the lack of information. But, we can keep the parallels between the companionship of finn and jake and shoko and the tiger in mind.