Soulbond (You may pair this creature with another unpaired creature when either enters the battlefield. They remain paired for as long as you control both of them.)
As long as Thundering Mightmare is paired with another creature, each of those creatures has “Whenever an opponent casts a spell, put a +1/+1 counter on this creature.”
Near Mint - $300
Lightly Played - $200
Moderately Played - $200
Heavily Played - $200
Damaged - $200
Near Mint Spanish - $300
Lightly Played Spanish - $200
Moderately Played Spanish - $200
Heavily Played Spanish - $200
Damaged Spanish - $200