Boseman, who plays the leader of the fictional African nation of Wakanda, gave his trophy to a man with no Hollywood connections.
"Receiving an award for playing a superhero is incredible, but it's even greater to acknowledge the heroes we have in real life", Boseman said onstage before signaling to Shaw in the audience.
MTV reverted to pre-recording the show, filmed on Saturday in a cavernous hangar at Santa Monica Airport in southern California, after broadcasting live previous year.
Boseman quickly handed off his best hero award to James Shaw Jr., who wrestled an assault-style rifle away from a gunman in a Tennessee Waffle House in April. She also posted a big ol" loving thank you to her fans, and a congratuwelldone to Schnapp for winning "Most Frightened Performance' (what a category) and the rest of the StrangerThings gang. Kim Kardashian accepted the award, telling the audience: "Thank you to my insane family for keeping it going this long".
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Messages about tolerance, trolls and gun violence punctuated this year's MTV Movie & TV Awards, where sci-fi drama StrangerThings won the main prizes.
Millie recorded a video message after splitting her kneecap, and amid thanking MTV, her castmates and Netflix, she delivered an eloquent speech on why the bullies ain't s***. Brown, just 14, made headlines recently for quitting Twitter after her image and name were repeatedly used in homophobic memes.
"If you don't have anything nice to say, just don't say it".
(Sadly, Nick Robinson couldn't make it.) Actor Keiynan Lonsdale, dressed in a white gender non-conforming ensemble, sent a powerful message of love and acceptance to anyone who needed it.