>>96745365
That sounds cool, but it also sounds like a book-keeping nightmare, especially making a new card mid-duel.
Let's set a simple point baseline. Each increment of 50 Atk or Def is worth 1 point. Kuriboh's Atk and Def would be 10 points.
Knowing that, how much should its level cost? How much should its effect be worth and how much should its downsides save on cost?
>One instance of battle damage negation
>Timing restricted to during damage calculation
>Requires Kuriboh itself be discarded