MCU: Every Single Marvel Movie Post-Credits Scene (And What They Mean)
6. Spider-Man: Homecoming - The Scorpion
The Scene
With Adrian Toomes in prison for his crimes (including terrorism, probably), the mid-credits scene sees him walking through his new prison home towards his cell. A call comes out recognising him and Michael Mando's Mac Gargan appears, having survived being dropped into New York Bay during the Staten Island disaster.
He has a gnarly looking arm splint and facial scars and demands that Toomes tell him Spider-Man's real identity as he has friends outside who would be interested in taking him down. Toomes denies he knows about Peter Parker's secret, and says if he knew who he was, he'd already be dead, before walking away.
What It Meant
Basically, that Gargan's alter-ego Scorpion is probably going to appear in the sequel to get vengeance on Spider-Man. Presumably his metal arm brace and the "tail" tech that was mentioned in passing for him earlier in the film will combine to become this universe's version of the Scorpion costume.