Fiddlesticks vs Cho'Gath

Channel Crowstorm (R) out of their vision, from a brush or behind a wall: if you're unseen when your spells hit, Terrify (Q) fears them too.

Aim the center of Reap (E) at the key target: in the center, they're silenced; at the edges, only slowed.

Channel Bountiful Harvest (W) to the end on camps and minion groups: you heal for part of the damage, and the remaining cooldown drops by 60%.

Place the effigies from A Harmless Scarecrow (passive) in key brushes: they replace your trinket, and Terrify (Q) can fear when you're mimicking one.

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.