It was not a drawing, but an actual photo, possibly computer generated. (Roush thinks it was an actual person in a Beast getup, though.) It was unmistakably of a young Beast, leaping through the air. And it was tagged Magneto.
Roush casually asked what the heck that was all about, and was told in a "isn't it obvious" way, "This is young Beast from the prequel they're gonna be doing. Magneto."
There's no real explanation as to what McCoy would be doing in a Magneto storyline, or how they would meet up. It is as random a choice of mutant as we're seeing with another X-Men: Origins film. I don't get it. Both Magneto and Wolverine are strong enough to stand on their own two storylines, which is why they were chosen for origin films in the first place. Is there some studio clause stipulating that they must choose a certain number of mutants to accompany the title character? It cannot be coincidence. I am willing to bet it means there will never be an X-Men 4, and that they are using these guest-star appearances to float more spin-offs. I'm probably overthinking that, and it is just a way to make more action figures.