This card has a variety of uses, but mostly saves you when you'd otherwise lose a duel.
Stopping yourself from losing a duel, and eliminating obnoxious options that remain on the duel zone are its main uses.
Combos with other cards:
Bakemon/Soulmon with this will instantly downgrade your opponent a level.
Ways to counteract it:
Playing Bakemon/Soulmon yourself will make your opponent think twice about it. Otherwise, option eater is your best bet.
This card is almost good enough to be included in every deck, unless they have other big combos to focus on. For that, I give it a 10/10.