Mike Deodato's "New Avengers" #12 cover shows Thanos as a massive bronze-colored statue in a pose reminiscent of the Mad Titan's appearance in Jim Starlin's "Marvel Two-In-One Annual" #2. The issue featured a battle that included Spider-Man, The Thing and a selection of Avengers culminating in Adam Warlock turning Thanos into a stone statue.
It's possible -- and the storyline would seem to be leading to -- the one responsible for repurposing Thanos as a statue on the cover for "New Avengers" #12 is the Mad Titan's son, Thane, introduced in the previous pages of Jonathan Hickman's Marvel event. Oddly enough, the key hint comes from Marvel's "Avengers Alliance" Facebook game where Thane was available to recruit into players' squads for a limited time in September prior to his "Infinity" debut. The "Avengers Alliance" wiki has a full list of Thane's abilities, which give a decent indication as to how Thanos gets into his statuesque state.
Thane's "Avengers Alliance" abilities include "Sealing Touch," "Amber Field," "Black Hand" and "Life and Death." It's the first two abilities that really seem to matter, given that looking at the cover, it's possible the material that surrounds Thanos-as-a-statue isn't bronze or red stone -- it's amber.
At this point, this is, of course, all speculation. It's possible Thane has nothing to do with Deodato's cover, and that there's no parallel to be drawn between this moment and the other time in Marvel history that Thanos became a statue. But his abilities and the beauty of calling back to a historical moment are too much to simply discount. Either way, readers will get their answers when "Infinity" #6 hits stores next week.
"Infinity" #6 releases in stores November 27.