It's NOT a monkey's paw, though. If anything it is maybe a deconstruction of a monkey's paw trope.
See, the One Wish Willow does not manipulate your wish to give you something you didn't ask for, nor does it backlash. Bear wished for a selfish wish. There were a ton of people throughout the film that wished for things and got exactly what they wished for. Heck, Bear's friend gets a billion dollars.
Like, I get that Bear's wish is corrupted, but he could've wished to be someone that Nikki liked. He could've wished to be better at talking to girls. He could've wished to be less cowardly. Those are less selfish versions of the same wish.
It wasn't the act of wishing that ruined his wish, but that he used his wish to manipulate someone else. He was the reason his wish was ruined.
There's a lot to disagree with here.
Ian is NOT the most malicious person in the movie because Bear literally rapes Nikki repeatedly. That isn't to say Ian is a good person, just that there is definitely a worse person in the movie.
Bear does NOT end his own life on purpose at the end of the movie, either. Bear tries to throw up the medicine to save himself and is only stopped because Wish-Nikki makes her own wish that inadvertently stops him.
Hell, the lesson of the movie isn't even to not wish for love! He could have wished for love! The point is that Bear never actually loved Nikki. Every scene reinforces that he doesn't actually care about her, that he doesn't really know anything about her. He doesn't even care that the Nikki inside of Wish-Nikki is being tormented. He tries everything to make Nikki into the person he wants instead of freeing her. He only cares about himself, and it isn't even until Wish-Nikki starts literally killing people that he even bothers to actually try to undo his wish.