Lullmage Mentor + Primal Vigor + Doubling Season + Exalted Sunborn

Lullmage Mentor

Primal Vigor

Doubling Season

Exalted Sunborn

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.

This intricate control lock turns a single countered spell into an overwhelming flood of Merfolk, establishing an absolute monopoly on the stack. When Lullmage Mentor counters an opponent's spell using its activated ability, its own triggered ability normally rewards you with a single 1/1 token. However, the combined replacement effects of Primal Vigor, Doubling Season, and Exalted Sunborn compound exponentially, scaling that single token into eight fresh combatants. With that massive influx of new bodies, you instantly have enough untapped Merfolk to activate Lullmage Mentor again, sealing the game with a near-infinite token army and infinite counters to stifle any subsequent plays.