Mono-Black Aggro is a mirror-style race full of small aggressive creatures like Forsaken Miner, Nighthowl Pursuer, and Sunset Saboteur, so Sunspine Lynx shuts down any incidental lifegain they might use to stabilize while its nonbasic-land damage is minor since they run mostly basic Swamps. Twisted Fealty can steal a key attacker like Desolation Prowler or Nighthowl Pursuer to swing back for extra damage. Impractical Joke's 3 damage is serviceable against their small creatures but our maindeck burn already covers this range, so trim a couple copies for more proactive plays. Keep the aggressive core intact since this matchup is decided by who curves out faster and applies pressure first.