Lullmage Mentor + Primal Vigor + Exalted Sunborn + Bard, King of Dale

Lullmage Mentor

Primal Vigor

Exalted Sunborn

Bard, King of Dale

How it works

1. Whenever an opponent casts a spell, activate Lullmage Mentor by tapping seven untapped Merfolk, countering that spell.
2. Lullmage Mentor triggers, creating a total of eight 1/1 Merfolk creature tokens.
3. Repeat.

When your opponent tries to cast a spell, you can use Lullmage Mentor's activated ability to counter it by tapping seven untapped Merfolk. This triggers Lullmage Mentor's first ability, and because token-doubling effects from Primal Vigor, Exalted Sunborn, and Bard, King of Dale all stack together to multiply the resulting Merfolk tokens exponentially, a single counterspell instantly generates an overwhelming horde of eight new 1/1 blue Merfolk creature tokens. With your newly widened army ready to tap, you can lock down the game by repeatedly countering every subsequent spell your opponents cast.