How do you get chamametchi on tamagotchi music star v6?

Make sure your tamagotchi generation is an even number eg 2. Then raise it well always keep its happiness up and weight & stress down also play a lot of games to max its skill points (it must be a girl) the evolution of your Tamagotchi should go something like this:

PETETCHI (white blob)

HITODETCHI (starfish)

CHAMAMETCHI (like the mascot but small)

CHANTOTCHI (the one you want)

if you don't get Chamametchi make sure your skill points are really high as this would make the difference.