Immortal Hulk: 10 Shocking Moments That Blew Fans' Minds

One of the most interesting concepts raised by the Immortal Hulk series has to be that of the Green Door, which is basically a portal that leads to the Below-Place, a version Hell where gamma mutants exist between their death and resurrection.

Although the concept of the Door is introduced as early as issue #2, it stays a sort of mysterious boogeyman for a considerable portion of the series, only properly explained in Immortal Hulk #10. This works masterfully, as while we get the idea that the Green Door has to lead to somewhere, nobody could predict quite where it would lead - meaning that the reveal it led to an irradiated Hellscape came as a big surprise.

While it's not quite as dramatic as finding out that the Hulk is immortal - or as visceral as seeing a man get ripped apart - this fun reveal is still worth its weight in gold for the potential implications for the future of Marvel and it's beloved radioactive beasts.