James Franco perhaps. (Harry Osborn from the Raimi Spiderman films). He was the funder for Otto Octavius's research in SM 2 (sidekick), I believe he had a painting done of himself in SM2 (or 3) and fought Spiderman at first and then Venom later on in 3 before dying.
Thanks. But what really stumped me was your clever wording about being, "sidekick to an octopus." I love cheesy monster movies and that clue really threw me at first.
By the way, great job on getting Ernest Borgnine. I thought he would be a really tough one to figure out.