Just rewatched Into the Spider-Verse (for the umpteenth time, I love the film so damn much) and I was reminded of a lingering question I've had since my first viewing: The nature of the Alchemax spider that bit Miles.
The initial implication is that it was potentially an escaped experiment of Liv's. However, the fact that it kept glitching, like all of the Spider Folk did because they were in the wrong universe, suggests that it, too, came from another universe during one of the earlier parallel universe collider tests.
Which leaves me wondering whether we'll learn more about that spider in Across. Especially considering Alchemax was originally introduced in Marvel Comics via Spider-Man 2099.