Prince and Peso both made by yours truly.
Made and worn for Game-Con 2011? 2010? and a small local cosplay gathering in 2013? or 2014.

Used the tutorial linked below, with a few subtle changes for the heads.
Used model magic for the nose which worked well. Felt for the eyes and mouth, yellow face outline, and the shell for the antennae thing on their heads. Foam ball for the round part.
Outfits were hand sewn by me. It was my first experience with pockets and the thumb pattern which was a good experience. Tights were bought in store and online, we used the cheap sandals bought on clearance at Jo Ann's, painted them to match our tights, ripped out the thongs and glued them to the tights.
Katamari ball (the smaller one) was made by pasting on small round cut up pieces of foam, and the second one was just random things taped on.