Why the cellar changed and now is full of spider webs

the-binding-of-isaacwrath-of-the-lamb

My basement cellar texture changed and now rooms are full of spider webs and fast annoying spiders. What's happened? Any hints how to go back and how to kill these spiderlings?

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Best Answer

In the DLC, there is always a chance of entering alternate versions of levels:

Basement = Cellar
Caves = Catacombs
Depths = Necropolis
Womb = Utero
Sheol = Cathedral

At the end of Womb/Utero, you have a choice of entering Sheol or Cathedral. All the other floors are random.