The MCU’s version of Thor definitely ranks among the most powerful characters to have appeared in the franchise’s movies, and Mjolnir plays a huge role in the hero’s identity. Though he eventually comes to the realization that he’s the God of Thunder not the God of Hammers in Thor: Ragnarok, it’s still an incredibly powerful relic in Norse mythology that helps him channel his strength. There’s also one ability from the comics in particular that could’ve given Thor a huge advantage while defending the universe from cosmic-level threats, but for some reason, it was never used in the films.
Mjolnir – which, fun fact, is actually older than Thor himself – was destroyed by Hela and only made something of a cameo in Avengers: Endgame. Which is a pity considering that we didn’t get to see its ultimate trump card ability at play: energy absorption and reflection.
In the comics, as early as Silver Surfer #4 from 1968, Loki manages to get up to his usual mischief and tricks Thor and the Silver Surfer into duking it out. When the chrome-plated galactic surfer unleashes the Power Cosmic on Thor, the Asgardian manages to absorb the energy blast into Mjolnir.
Going one step further in Thor #22, Thor battles Thanos when he’s going after the Illumination Stone and ends up on the receiving end of a blast of energy. He once again absorbs the blast using Mjolnir and this time sends it back his way with “its power magnified a hundred-fold.” That would’ve been pretty handy against the Mad Titan and his lackeys in the MCU, but maybe next time.
After all, Thor‘s signature weapon will very likely be wielded at some point by Natalie Portman’s character Jane Foster in the upcoming Love and Thunder, and maybe there Marvel will decide to explore some of its abilities that we’ve yet to see in the MCU.