The Cthulhuphant is a tanky strength beast that can charge into a battle almost fearlessly, wreaking havoc on nearby enemies with his crippling passive slow and large area effect damage. At early levels he's able to kill difficult neutral creep camps with use of "Hook 'em", and gain an early level advantage that he can gank frequently with, using "Trample" for the burst damage and stun. If playing him in the lane, he can charge into creep waves and send projectiles flying to stun enemy heroes from a far distance--giving allies an opportunity to follow up with additional disables and damage output.
Cthulhuphant's greatest weakness is keeping up with his foes and dealing lethal damage. After using Trample, he has no other disables aside from his passive aura and may find himself falling short of killing an enemy. However, even with no survivability items early on, he can withstand a great deal of damage. For this reason, ghost marchers are an important pickup to help boost his attack damage and allow him to keep up with his prey.