The latest trailer for Avengers: Endgame provides few definitive answers about the Marvel Studios sequel, but teases enough new details to fuel plenty more theories. Chief among them is by what means Thanos arrives in the final moments of the footage.
Some fans are already speculating the Mad Titan is employing the Bifrost, the comic energy used by Thor and other Asgardisn to travel the Nine Realms, to instantaneously span the cosmos. That's because the shimmering effects are reminiscent of Thor's many arrivals in the Marvel Cinematic Universe, most recently in Thor: Ragnarok and in the final act of Avengers Infinity War. What's more, it's significantly different from how it looked when Thanos used to Space Stone to open portals to Titan and Wakanda in the 2018 blockbuster.
However, the Bifrost's energy signature is comprised of all the colors of the rainbow -- an apt touch, given that it's referred to as the Rainbow Bridge -- whereas Thanos' teleportation energy in the trailer is blue. More importantly, Asgard was destroyed at the end of Thor: Ragnarok, and Heimdall (Idris Elba) used dark magic in the opening scenes of Infinity War to summon the Bifrost and teleport the Hulk to Earth. With his new weapon, Stormbreaker, Thor is able to tap into the Bifrost, as he did in the final act of Infinity War to bring Rocket Raccoon, Groot and himself to Wakanda, but why would Thanos be able to access that energy. And why would he need to?
It isn't the Bifrost, but instead more likely it's a teleportation beam from Thanos' flagship, Sanctuary II, introduced in Ragnarok and seen earlier in the Endgame trailer. A similar blue energy in Infinity War whisked away Black Order members Proxima Midnight and Corvus Glaive following their defeat by Captain America and his Secret Avengers.
That beam was was fainter than Thanos', but that could be that it originated from one of the Q-Ship's rather than from Sanctuary II.
But why wouldn't Thanos merely use the Space Stone again to open a portal? It's possible the snap damaged the Infinity Gauntlet, limiting the Mad Titan's ability to use the powers of the Infinity Stones.
There are a few possible explanations as to how Thanos is traveling in Endgame, but we can probably be certain its not by using the Bifrost.
Directed by Anthony and Joe Russo, Avengers: Endgame stars Robert Downey Jr., Chris Evans, Mark Ruffalo, Chris Hemsworth, Scarlett Johansson, Jeremy Renner, Don Cheadle, Paul Rudd, Brie Larson, Karen Gillan, Danai Gurira, Benedict Wong, Jon Favreau and Bradley Cooper, with Gwyneth Paltrow and Josh Brolin. The film arrives April 26.