Malphite vs Cho'Gath

Save Unstoppable Force (R) for when the enemy carries are grouped: nothing stops your charge, and the impact knocks every enemy in the area into the air.

Cast Seismic Shard (Q) before engaging or to escape: it slows the target and gives you the speed it steals.

Take your trades while Granite Shield (passive) is up: it absorbs 10% of your max health, and Thunderclap (W) then triples your bonus armor.

Against a champion who lives on autos, start your trades with Ground Slam (E): it lowers their attack speed, and its damage scales with your armor.

Keep moving against him: Rupture (Q) strikes an area on the ground, and an enemy standing still takes a knock-up, damage and a slow.

Punish him when he goes for last hits: Carnivore (passive) restores health and mana for each unit he kills, and he lasts a long time in lane if you let him farm.

If you have range, keep your distance: his kit has no dash, only the slows from Rupture (Q) and Vorpal Spikes (E).

Don't stay in melee range at low health when Feast (R) is up: its true damage ignores your resistances, even if you're a tank.