A screenshot of Wily Stage 5 of my fangame, Megaman F, showing none other then the Pre-Final Boss, Zero. Unlike most others however, I studied his X1 Design and pixeled from scratch a whole new 8-bit Zero sprite. It's not perfect, but considering this took a good 4 hours to make (The sprite, the level is already in the game.). I think it came out satisfying. or whatever.
Zero here is actually an unstable prototype of himself, close to his final design, but when you (if you can) defeat Zero, he shuts down with severe damage, then Dr. Wily repairs him and finishes the final version of Zero, to be put to rest for years to final his real goal, to kill Megaman X.
(He appears via capsule, it opens up, there is a cutscene, and Wily flies away after unleashing the Zero prototype)