Avengers: Infinity War - 14 Plot Hints You Might Have Missed

6. Groot Helps Thor Build Jarnbjorn

We know that Thor spends at least a decent chunk of Infinity War hanging out with the Guardians of the Galaxy, and Rocket (Bradley Cooper) and Groot in particular.

In the main Infinity War trailer, there's a glimpse of Thor firing lightning around a room as Rocket and Groot appear to look on, which prompted a fan theory both delicious and plausible, that Groot will help Thor craft his new weapon, the battle-axe known as Jarnbjorn (which has been featured extensively in the film's concept art).

The prevailing rumour is that Groot, who apparently finds a mentor during Infinity War, uses part of himself to craft Jarnbjorn's wooden handle, perhaps imbuing it with some additional powers as a result.

It's a little out-there, perhaps, but it would be an agreeably unique way to cement Groot and Thor's fast-growing friendship.