You see a volatile rift.
Notes
It is part of the fight against Rotrender. It can be seen after the 
Contained Rift is used to transform a player into 
Avatar of Storm. It lasts for 10 seconds, becoming a 
Pulsating Rift afterwards.
It is part of the fight against Rotrender. It can be seen after the Contained Rift is used to transform a player into Avatar of Storm. It lasts for 10 seconds, becoming a Pulsating Rift afterwards.