Hello mate! It ain’t a tool per se - yet - thus no screenshots.
It is a collection of pixel art pieces that you can just slap them over each other - the positioning is already done for all of them, but you can mess around - using your favourite pixel art editing tool and voilá! Content is split in folders to match the body shape you have picked, there are literal millions of possible combinations.
TL;DR, pngs that you can just copy + paste over each other to build any character.