88. Avengers vs. Nefaria (Avengers # 166 vol. 1)
Count Nefaria was one of the earliest Avengers villains, attempting to take them on sans powers. That did not work out so well for him, and he was a minor character the next decade or so.
He came to preeminence again in Avengers #164-166, a dynamite three-parter by Jim Shooter and John Byrne, where Nefaria reformed the Lethal Legion with the villains Power Man, Whirlwind and the Living Laser, whose powers were increased by Nefaria to fight the Avengers.
We soon learn, however, that Nefaria experimented with their powers only so he himself could gain their powers! He has a scientist do so and once he is powered, he fatally wounds the scientist and takes on the Avengers!
He handles them easily, in a series of great panels by a young John Byrne. What’s especially cool is the battle between Nefaria and Thor, where he man-handles Thor (who, to his credit, never gives up) including the awesome scene where he just stops Thor’s hammer mid-swing.
Eventually the dying scientist catches up with Nefaria to tell him that the energy transfer is quite unstable (and it is aging Nefaria rapidly), and Nefaria is clearly losing some power, so ultimately, the Avengers just pile on him with all they have until he is very weakened, at which point Vision flies high into the air, turns as hard as diamond and then drops to the ground, crushing Nefaria and finally takes out the man who took on the entire assembled Avengers!