A MultiVersus dataminer has found evidence that Gizmo and Stripe are one interconnected character that can likely be swapped between, similar to Pyra and Mythra in Super Smash Bros. Ultimate.
MultiVersus just started its first season a couple of days ago and alongside the launch was the reveal that Black Adam and Stripe from Gremlins will be joining the game sometime during the next few months. Anyone who's been keeping up with MultiVersus leaks might have been a bit confused as to why Stripe was announced and not Gizmo, but it looks like there's an explanation for it.
As pointed out by MultiVersus leaker multiversusie, files found within the game reference a character called C023A and C023B, implying that it's one fighter that can somehow split into two. We know from the character announcements and the voice lines associated with these two files that C023A and C023B is referring to Stripe and Gizmo, implying that they're one connected character that can be swapped between, seemingly like Pyra and Mythra in Smash Ultimate.
There are several bits of evidence that support this idea. A character avatar photo for Gizmo that's unlocked through character mastery was readded to the game, which would only make sense if he was actually playable in the game in some capacity. Tony Huynh also made reference to a character with a bow and arrow recently, with many making the connection to Gizmo using the flaming bow and arrow in the first Gremlins, something that would only make sense for Gizmo to do and not Stripe, again supporting the idea of separate movesets that can be swapped between.
It's also possible that Gizmo is a separate skin for Stripe, similar to how Jake and Cake work, but most Legendary skins aren't listed in the game like this so it seems more likely that there's some kind of mechanic that lets players swap between them. Some have suggested that Gizmo summons Stripe at a certain percentage, or it could simply be a special move that swaps them, with the two having different moves than one another.