C is for Chameleon

Chameleon is Spider-Man's first villain - a master of disguise and impersonation, he can be anyone, anywhere. Which seems like a pretty sweet setup for a villain. I mean, look at Mystique over in the X-Men books, she's taken pretty seriously. Chameleon's brother was Kraven, who's always been taken seriously, so that's got to hurt too.
As far as I can tell, Chameleon has been killed 3 times, and all three times it was just ignored. I mean, you know you're a barely worth a darn character when no one even cares that you're dead. Kraven, his brother? Died once and has pretty much stayed dead. A true sign of comic respect.
Chameleon has squared off not only with Spider-Man but also Daredevil, Hank Pym (Ant-Man, Giant-Man, Yellowjacket, Wasp, etc...), he even went at the Hulk a couple times. BUT,in his career he's been bested by Aunt May.
Look, everyone has an embarrassing loss. I mean, the Power Pack is a bunch of kids and they got over on their fair share of villains, these little villainous trip ups happen to the best of them (Thanos AND Dr. Doom have both been beaten by Squirrel Girl, you know). But we're talking AUNT MAY here. A frequently ill, sometimes dead Octogenarian. And she beat him with cookies.

Sad.

Poor Chameleon.