I would not suggest what karolbr95 said about using FNVEdit to remove stuff, use the GECK.
FNVEdit could do, only if you know what you're doing, for example, creature 1 may (and will) be connected to other stuff such as the fommlist, etc.
So by deleting only the creature, there will be problems with the mod because it will try to find the creature because of some other stuff but the creature itself would not be available anymore.
It is faster and easier to use the GECK, because using the GECK, when you are about to delete something, it will say that it is connected to other stuff then with one click you can make them obsolete.
So i would suggest you to use the GECK over FNVEdit.
But anyway, i think there is already a version without the spiders.
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"All we have to decide is what to do with the time that is given to us"-
Gandalf the Bla- I mean the white.