Looks like a home-made anvil.  While there are a lot of hornless anvils, I've never seen a mass-produced anvil that had such a thick, but unsupported heel.  That's a mighty long cantilever for the heel, and I don't see any indication of a faceplate being welded on.  More likely it was cut from a thick billet with a plasma cutter.

Still a mighty fine anvil and one I'd be happy to have in the shop.

a bridge anvil??

 

Bridge anvils have two legs. Looks like a large drop with a square hole made in it. The edges aren't rounded over either. Now, coalforge, you have the right if it tho. Its a large chunk of steel you can forge steel on, so its an anvil regardles of its pedigree

Weird...and lovely... all at the same time. 

Looks like a drop from the cutting table to me to.  Someone had the bright idea that Hey it looks like an anvil and put in that hardy hole.  If they had thought about it thy might have moved it to the other side and closer to the sweet spot.