WiseWolfOfYoitsu |
The hand is basically allowing you to cast touch spells at range. It doesn't provoke because it's not actually moving as a creature. Now, a creature can ready to hit the hand as it comes into range, but at lower levels will be very hard to hit/kill. It's got AC equal to 22 + caster's INT Mod, is Incorporeal, and 1-4 hp dependent upon the roll at the casting.
It can be a very annoying spell for foes at higher levels unless they get rid of it. Metamagic low level spells like Shocking Grasp up to a 4th level spell and hit that giant a couple times with 10d6 electric damage from a safe distance and see how fast he takes that hand out. Now, you won't generally be doing this with challenging foes, but it can harry lesser fights rather easily.