Just the one, so far. But that universe I got dragged into - there was a variant of him, there, and a number of other superheroes besides. So who knows? Maybe we're just getting started.

[He wouldn't disagree that it's inexplicable, even from the perspective of someone who knows a bit more about Spider-Man than the general public. But he's also had several years to get used to his existence, if not the details.]