On the Steam Workshop as of October 31st, Rain World has had one mod rise from the ground like a zombie to take the community by storm. The haunted mod has come out and scared people playing the game because you can’t expect what isn’t there to appear. With the haunted mod, you are stalked by slugcat apparitions, have moving echoes, and much more to occur with random chances.
As from Lolight2‘s YouTube video on it, there’s a variety of things that can happen. From a long slugcat coming through a pipe only to disappear when you approach it, and for a long slugcat to be standing and watching when you enter a room, a lot is possible. It can even spawn seemingly normal slugpups that’ll run away and avoid you at all costs while looking strange, and make lizards spawn and then disappear. The mod contains many spooks, that won’t outright harm you yet are bound to give many scares while letting you play the game as you usually would.
If you want to have odd things happening at times, I highly recommend the mod because stuff will happen with little-to-no explanation for it other than the mod, and sometimes it’ll just leave you paranoid thinking something will happen when nothing happens.