Not a single flavour, but a range of flavours, with the sour levels ramped up, much like Yellow Snow.
Potential SuperSour lines:
Lemon (Yellow Snow)
Apple
Cherry
Bubblegum
Lime
Watermelon
Grape
Peach 🍑
#Sneak SuperSour
mystic fable
nocturne forge
sour, apple,grape,bubblegum is out the question with them discontinuing the flavours but a sour cherry a little but more sour with cherry bomb omgosh 
mystic fable
sour, apple,grape,bubblegum is out the question with them discontinuing the flav...
I don't think it IS out of the question, personally. In fact, I think having removed those flavours gives more freedom to release the new ones without oversaturating their existing lines. And cherry has quickly become a flavour people complain about not being as good as it used to be, so that could be changed to a "supersour" too.
lone glacier
I think breakfast orange should be added to this list too, a nice sour breakfast orange would be class! I tend to mix 1 scoop of yellow snow with 1 scoop of breakfast orange in my sneak tank bottle and its absolutely delicious!
Or perhaps a sneak sour droplet bottle so you can add the sourness to any flavour you want?