Kog'Maw vs Locke

Start your trades with Caustic Spittle (Q): it reduces the target's armor and magic resist, and its ranks also give you permanent attack speed.

Activate Bio-Arcane Barrage (W) right before the teamfight: it extends your attack range, and your autos deal damage based on the target's max health.

When an enemy runs at you, cast Void Ooze (E) between you and them: the trail of ooze slows everyone who crosses it.

Save Living Artillery (R) for targets below 40% health, where it deals its max damage: each shot fired in quick succession costs more mana.

Back instead of staying in lane at low health: Silver Stake (passive) adds damage to his autos that grows with your missing health.

Trade after Ashen Pursuit (E): it's his only instant movement, and its 10-second cooldown only resets if he gets a takedown.

During Soul Ignition (W), only hit him if you can kill him: at the end, he heals back part of the last damage taken, yours included.

Marked by Purgatory (R), stay above its threshold: if you have a heal or a shield, use it, because he seals marked enemies who drop below it.

If the Purgatory (R) artifact lands, hold the area where it fell: by picking it up, Locke raises his execute threshold for each sealed champion, for the rest of the game.