TR_Merc's page

Unless your GM is deliberately throwing deceptive creatures at you, it shouldn't be too hard to guess the correct skill...

Maybe not deliberately, but he grabs obscure stuff to throw at us and sometimes, it can be confusing. Like spiders with special abilities. Is that Knowledge Arcana (Magical Creatures), or Knowledge Planes (Outsider), or Knowledge Dungeoneering (Aberration).

He also confuses things sometimes. Some of the few times he actually tells us to make a knowledge check, he asks for knowledge Geography to find something in a city which would be a knowledge local.

Okay, to be blunt your GM is being a tool. That said, it requires no action to make a knowledge check, so just ask to roll every one you have.

I would, but if you roll the wrong skill, he is not allowing you to roll a different skill. I came up with the idea of just rolling every knowledge already.

So I have this DM who is constantly asking us what Knowledge check we want to make to identify something, and if we use the wrong knowledge skill said, we fail to identify what we are fighting.

So the question came up if the DM is supposed to tell you what knowledge skill to make or any skill checks to make, and I can't seem to find a rule anywhere about that.