I'm talking about in every single appearance he ever made, can anyone mention all of them?
This is off the top of my head:
1. When Mysterio turned himself into "Spider-Man" in ASM.
2. When Mysterio turned himself into "Spider-Man" and robbed the jewelry store in "Spider-Man: The Animated Series".
3. Probably the most classical, the Chameleon in a Spidey mask and framed our hero for the first time in ASM.
4. Spidey was again "framed" when the Spider-Carnage destroy NYC in "SM: The Animated Series".
5. When Peter lost his memory, and Doc Ock convinced Spidey that he was working for the "doctor" himself.
Ugh I'm out, anyone else can remember the rest?
*continue from number 5 :D