Hmm, the fan art theory sounds like a lead! But that wouldn't be too fun. No, that would make things WAY too easy.
Do you remember the name the magazine you saw it in? If not exactly, could you narrow it down?
And whether or not you remember the name of the gaming magazine, that you saw the Mario page in, do you remember what month the issue was released in?
and if not, do you remember when you received it? Which now that I think about it, if you read the magazine in a different month than it was printed, that might not be helpful...
But if you do remember the month, or season, that would be great! 😃
Other things that could help:
1: Sometimes it's not the lost thing itself you want to find that will help you find it. Sometimes it's things that are associated with what you want (or need) to find! 🧐
Try to remember what else was in that magazine! What other article can you remember that were on that page, or any other articles or images that where in that issue.
2: Narrow down with the information you have. I don't know anything about resident evil, but you do! 😃
Which resident evil character, or characters, where in this cross over? That could give you a BETTER idea of the year this magazine came out! It's not likely that the characters would be from a type of resident evil game that didn't exist yet, so your best is to try to remember which character you saw. Heck, after you figure out who they were, you can do a separate search for that resident evil character so you can find it. Or you could google Mario and the name of the character!