Toss with half the remaining white cookie crumbs and the chilled pudding. You probably won't need all of the pudding. Line new, clean kitty litter box. Put mixture into litter box. Put three unwrapped Tootsie Rolls in a microwave safe dish and heat until soft and pliable.
Shape ends so they are no longer blunt, curving slightly.
Repeat with 3 more Tootsie Rolls and bury in mixture. Sprinkle the other half of cookie crumbs over top. Scatter green cookie crumbs lightly over the top, this is supposed to look like the chlorophyll in kitty litter. Scrape them on top of the cake and sprinkle with cookie crumbs. Or, only spread 5 of the remaining Tootsie Rolls over the top.