From WoWWiki
The Incredible Hulk is a Lich King heroic achievement in Utgarde Pinnacle needed for the 
25 
[Glory of the Hero] meta-achievement, which in turn rewards the [Reins of the Red Proto-Drake].
Strategy
The tank must pull both Svala Sorrowgrave and a Scourge Hulk and tank them both while the raid damages the Scourge Hulk to a low enough health that it will be killed by the Ritual of the Sword's AoE damage. It is advised to ensure this achievement is not botched that nobody uses DoTs as it may prematurely kill the add. The tank has to stand on the table tanking the add while the sword is lowering and take the AoE damage as well. The achievement will be earned the instant the add is killed by the AoE.
See also
Videos
Svala Sorrowgrave to kill a 
[Glory of the Hero] meta-achievement, which in turn rewards the [Reins of the Red Proto-Drake].
