3. A Surprising Cameo
In a real blink and you'll miss it moment, The Avengers featured a surprise cameo from Huginn and Munnin. Those names might not immediately ring a bell, but they're pretty important characters in Marvel and beyond - they're the ravens who serve as Odin's spies on Midgard and the other realms he watches over with his one good eye. After sending Thor to Earth, Odin clearly wanted to see for himself what Loki was up to as the ravens can be spotted flying around the mountain peak where Thor and Loki are talking before Iron Man interrupts. This was a clever inclusion by Joss Whedon and a nice way of tying everything together, while also rewarding eagle eared fans.