What is the mage spell...

[Coagulation]

that has that busting ball of energy?

It starts at 3:10 - http://www.youtube.com/watch?v=f2GRfeWuBI8

He's not using zuriel's staff so how is it miasmic? What is it?

 

[Rioterz]

That is ice barrage my friend.

 

[Coagulation]

if it is ice barrage why is it a different emote?

 

[lazy pker]

look here: http://runescape.wikia.com/wiki/Miasmic_Barrage

 

[iKillChickens]

Ice barrage.

 

[Doodles]

Yep icebarrage. 502 wow. But anyway probably cause his using HD? How about you give it ago.

 

[JRSmithfan1]

Ice barrage or Miasmic Barrage.
Check the description. That's what it said.