Abilities of Cho'Gath
Spell skill priority is an important winning factor for Cho'Gath. Understanding the abilities of Cho'Gath in League of Legends is another. Below you can find all the relevant information on Cho'Gath abilities. In order for item builds you should check the build for Cho'Gath.
Passive: Carnivore
Whenever Cho'Gath kills a unit, he recovers Health and Mana. The values restored increase with Cho'Gath's level.
Rupture
Ruptures the ground at target location, popping enemy units into the air, dealing damage and slowing them.
Cho'Gath ruptures the ground, Knocking Up enemies for e5 second, dealing totaldamagetooltip magic damage, and Slowing them by e2% for e3 seconds.
Feral Scream
Cho'Gath unleashes a terrible scream at enemies in a cone, dealing magic damage and Silencing enemies for a few seconds.
Cho'Gath roars, Silencing enemies for e2 seconds and dealing totaldamagetooltip magic damage.
Vorpal Spikes
Cho'Gath's attacks release deadly spikes, dealing damage and slowing all enemy units in front of him.
Cho'Gath's next 3 Attacks launch spikes that deal flatdamagecalc plus maxhealthpercentcalc of the target's max Health magic damage and Slow by slowamountpercentage%, decaying over slowduration seconds.
Feast
Devours an enemy unit, dealing a high amount of true damage. If the target is killed, Cho'Gath grows, gaining maximum Health.
Cho'Gath ravenously feeds on an enemy, dealing rdamage true damage to champions or rmonsterdamage to minions or jungle monsters. If this kills the target, Cho'Gath gains a stack, which causes him to grow in size and gain rhealthperstack max Health. Only rminionmaxstacks stacks can be gained from minions and non-epic jungle monsters.
FAQ on Cho'Gath
What do you max first on Cho'Gath?
Most Cho'Gath pros max out 
Vorpal Spikes first.