Where is Mother Long Legs/Terror Long Legs Unlock?

[Tahman321]

I can't seem to find it on the wiki.

[Redlegoguy1]

It's in the rot. It's shown on the wiki map, it's sort of in the middle right part of the depths. I don't think the part of the room it's in is explicitly one way, but it's definitely way easier coming from the adjacent exit, which can be reached by taking what used to be the unfortunate development path.