I think it's adorable: it's about half the width of a typical guitar effects pedal, and maybe 80% of the usual length. It's so small that a nine-volt battery won't fit inside: you have to use an external power supply.
It's a Mooer "Pure Octave", from their "Micro Series Compact Pedal". The large white pedal chooses the harmony notes: e.g. "+2 -1" produces one octave below, and two octaves above. The small black knobs are "SUB" (the lower octaves), "DRY" (presumably, the wet/dry mix), and "UPPER" (the upper octaves).
I haven't had a chance to play it yet -- but I bought it on the strength of some of the YouTube demos.