Summary:

Strange’s second spell does not have anything to do with memory. Maybe Peter should have expected it, as the previous one acted in the same way.
Instead of erasing the memories of the ones he loves across the world, the incantation instead plucked him from his universe, erasing all traces of his existence, and threw him into a new one.
Now seventeen, having lost his family and friends, he finds himself in a strange world, alone in one of the most dangerous cities across all dimensions.

Or : Peter needs money to survive Gotham and picks up a pizza delivery job.

Spider-Man/DCU (Specifically Batman) Crossover