You are allowed to make three changes to the Ultimate Marvel Universe. However they must affect Spiderman, X-men, and the Ultimates in someway (if one change you make affects all three the other two can be used to do whatever you want to the verse).
However you must also "drop" 3 fictional characters that are not from any type of Marvel verse into the Ultimate verse and one of them at least must be a villain (Prep-type or serious threat to a team of heroes). They may not all also be from the same universe i.e. only one from their own verse (Don't try to scrue the rules by using alternate universes of DC because if its DC it must only be one DC character).
What changes do you make? What characters do you choose to drop in Marvel? How do they affect the Marvel Verse?