OK, this isn't really a 'kemushi', it's a caterpillar that will no doubt turn into a beautiful butterfly once we have released it into the wild, but you ain't gonna be a butterfly on our time buddy!
This is 'Sansho' 山椒 that he is eating - a Japanese or Aisian pepper plant! It's adds a nice flavour to our cooking...but only without the caterpillar!