Avengers: Infinity War - 15 Obscure Easter Eggs You Might Have Missed

2. A'lars, Father Of Thanos

When Thanos and Gamora arrive on Vormir, they're met by the keeper of the Soul Stone, who is none other than Red Skull (Ross Marquand) in spectral form.

He greets Thanos by referring to him as, "Thanos, son of A'lars", but unless you're really paying attention, the line is easily missed or glossed over.

This is, of course, a nod to Thanos' comic book parentage, with the Mad Titan's daddy being A'lars aka Mentor, a member of the superhuman race known as the Eternals.

While this might sound like a throwaway reference, Kevin Feige has confirmed that an Eternals movie is in fact in the works, so Infinity War provides our first lead-in to the film, albeit an incredibly sly one.