Joker vs. The Fantastic Four
So...
Reed was f*cking around again with dimensions and whatnot, and wound up with him, Ben, Sue and Johnny stuck in Gotham. They joined forces with Batman, and began to lay waste to his enemies. Joker believed that Batman had found new best friends, and Joker didn't matter anymore.
(I consider this a very plausible scenario)
vs.
1. Joker gets a month and a half to prep. He basically lays a trap/ambush or whatever for the FF. He's allowed henchmen and such, as well as Harley Quin
2. If thats not enough/ too much, how much prep would be ideal for Joker to take them down?