No prep time. They fight to the death(or until one Pokemon faints). Both are bloodlusted.
@st0nnec0ld: But like I said, Pikachu can't scratch arceus...
Well Arceus is the "god" of Pokemon except for this guys...
Mewtwo, Deoxys, the legendary beats of Johto (since Ho-oh is their god), Ho-oh (IMO Arceus did not created Ho-oh), Castform, Porygon, Porygon2, and Porygon Z because Arceus didn't create them (except Ho-oh but IMO no) but that's off topic.
Arceus one shots Mew.
Tonight: Arrow comes back in a Flash, runs into Mob City, the Black Friday trilogy ends, Sports Ball is played.