So I had an idea to fuse two Undertale chars into one, to see what I'd come up with. I ended up coming up with this idea for a form of Sans in which W. D. Gaster has managed to merge with him to help him against Chara, creating the hybrid known as NaNs (named after the computer error acronym NaN, or 'not a number'). His design is also heavily based off a Gaster Blaster.