When an effect resolves that was activated by your opponent's Effect Monster on the field, they can discard 1 card. If they do not, that effect is negated.
NM-Mint Limited - $10.90
Lightly Played Limited - $9.80
Moderately Played Limited - $8.70
Heavily Played Limited - $7.60
Damaged Limited - $5.50
NM-Mint Limited Non English - $10.90
Lightly Played Limited Non English - $9.80
Moderately Played Limited Non English - $8.70
Heavily Played Limited Non English - $7.60
Damaged Limited Non English - $5.50