I don't know which mod adds them, but there are blocks in the map https://gamebanana.com/mods/34267 that look like normal zippers, but if you try to hold on to them, you will instead literally hold them in your hand...
I found that if you take it out of the room, two things happen:
- the spikes that were previously on the block will disappear
- if you trigger it, the game will crash
Usually don't report crashes but this seemed important, since it would affect every map that used something like this.
I've attached the related crash logs.
Edit: realized you can't mask links here so I've replaced the map name + link with just the link
GameBanana
Celery... A Celeste (CELESTE) Mod in the UI category, submitted by LegS