Spider-Man: Far From Home nearly had a cameo appearance from Donald Glover as Aaron Davis. Glover had a small supporting role in Spider-Man: Homecoming, whose petty criminal was seen buying weapons stolen by Michael Keaton’s Vulture, and later gave Peter some information after a none-too-impressive attempt at interrogation, despite failing to find him in any way intimidating.
Aaron Davis is a character taken from the Ultimate universe of Marvel comics who becomes its version of the Prowler, a skilled cat burglar armed with a battle suit and gauntlets capable of firing shock waves. In Spider-Man: Homecoming, Davies had yet to adopt the supervillain mantle, although his attempt to purchase high tech weaponry suggests he was on his way there. Also, a mention of his nephew was a reference to Miles Morales, which confirmed the existence of the future Ultimate Spider-Man within the world of the film. A different version of Davis was featured far more prominently as a villain in Spider-Man: Into the Spider-Verse, seeing him fully formed as the Prowler and an employee of the Kingpin.
The story of Glover’s potential involvement came from THR, relayed during an interview with Spider-Man: Far From Home writers Chris McKenna and Eric Sommars, revealing that the idea was one of several bandied about that never made it into the final film. They both loved the character and wanted to bring him back, but after the story’s development ended up taking Peter and his classmates to Europe so quickly, the idea was dropped since it simply didn’t fit anywhere. McKenna lamented, “Some ideas you just have to give up.”
Glover has further history with Spider-Man beyond the MCU/Sony outing, having previously voiced Miles Morales in a couple episodes of season 3 of the Ultimate Spider-Man animated series. He appeared as part of a multi-episode arc that saw Norman Osborn travel across the multiverse to gather DNA samples from the various Spider-People to transform himself into the formidable Spider-Goblin.
Although the capacity in which Glover would have appeared was not specified, it’s likely that it would have been something like a brief scene seeing Peter clashing with Davies as the Prowler, possibly foiling a robbery that the latter was in the middle of committing. His presence is potentially an important one, as it's likely through him that Miles Morales would be introduced into the world of the films, and from there the use of multiple Spider-People like those seen in Spider-Man: Into the Spider-Verse. Even though it would have been nice to see him again in Spider-Man: Far From Home, as the film stands there really wasn’t the space to include him without it seeming forced, and the decision to leave him out was probably the right one in the end.