In his first form, he only targets one player with ranged attacks. This can be ignored if you have a good armour. The slam must be dodged by running away. He also attacks all players in room with magic, however, you can easily notice when he's going to do this. He floats in the air, spinning and seemingly drool coming out of his mouth. Right after this he will hit mage every player in the room. Activate magic protect when you see him spinning to avoid this attack.

 

The second form isn't as easy. He will still float and spin (as charging) but he is not attacking. Instead, when he is standing on the ground, he will open his mouth and blast every player with magic. This is much rapier and harder to react, but praying magic instantly after seeing him open the mouth should do it.

Hey, thank you for your submission :)

 

I just toyed around with the boss a little to get a cleared idea of his mechanics. In his first form, Night-gazer uses both a single-target ranged attack and a single-target magic attack. He seems to use them randomly, unless you pray against either style, in which case he will attack exclusively with the combat style you're not protected against.

 

His floating-spinning attack does indeed do magic damage to multiple targets. I've previously never noticed this attack doing magic damage, as I'm always praying against magic while fighting this boss, and the attack's projectile looks _exactly_ like the single-target ranged attack's projectile. Talk about confusing. In addition, this attack is also what causes your energy to be drained - praying against magic won't prevent the energy drain, either.

 

The blast attack you describe for the second phase is the attack that has a chance of stunning you. I wasn't able to reliably activate prayer against this in a timely fashion. I did notice that it didn't hit particularly hard, though, unlike the potentially unavoidable slam follow-up :-X

 

I'll update the bestiary entry to take this into account. Thanks!

 

Edit: hah, it has as much text as Stomp now. At least we're being thorough :-P