PVP?

Does Horizons have a PVP system? Dragons vs. Bipeds??

Both can throw snowballs, but other than that, no.

There's an arena on Blight, but it's more of a testing tool than anything else.

I heard someting about a spire that you could go to and get teleported to some PvP island..what happened to that?

The PvP arena is on the live shards as well. you have to port to the spire's shadow area then climb to the top of the spire and use the portal up there. There is no open PvP, only that arena.

I went there for the first time yesterday, paid my 1s,400c and, upon landing in the arena, took off toward the left, across the bridge, and was promptly stuck in a chasm on the left side of the rocks- fair warning to all here- its deep and no way out. Stay on top of the rocky area to your right when you come off the bridge onto that island!