An invented form, resembling a cross between a jaguar and a pangolin; a densely muscled feline shape coated in scales.  Like all of Johann's invented forms, it has a human-speech-compatible throat.
The bandersnatch form has some flaws, though; the main one being a comparative lack of endurance.  It's not well adapted to hostile environments (extreme heat or cold, either one), and the design compromises needed to make the front paws capable of functioning as hands lead to issues if the bandersnatch has to spend too much time on its feet.  On the other hand, it's fast, sneaky, powerful, versatile, can "see" with its eyes closed, and is probably the single overall most effective combat form Johann has access to.

-1 echoes of the beast (ability to see thermal/IR - functions based on secondary sensory organs rather than eyes)
-1 claws
-2 inhuman strength
-4 supernatural speed
-4 supernatural toughness
+3 catch
-1 crushing bite (+2 weapon rating to overcome armor)

(unspent: +1)
+6: fists, athletics
+5: investigation, alertness
+4: lore, stealth
+3: empathy, conviction, might
+2: discipline, survival, scholarship, rapport
+1: presence, endurance, deceit, performance

details on individual forms:
male, mottled grey-black scales - swaps stealth & investigation skills; this form is a little bit leaner and more serpentine in build.
male, forest green with gold markings (similar to those from that wolf in the videogame Okami)
female, pure black (shiny, like obsidian)
female, red-orange with fire-like markings - swaps stealth & might skills; this form is a bit stockier and more angular in build.