Yea, i think it would be a stalemate but eventually Galactus would come and destroy them both. Terrax because he was so incompetent to destroy a weakling like Apoc and Apoc because he's an idiot to fight a herald to galactus. And just so everyone knows, I never said that i though Apocalypse had any chance against Big G, im just saying that he much more powerful than people think and that i think he could take ONSLAUGHT in a brawl, who i think is very overrated.
Terrax hocks a loogie at A-poc that barely grazess him. That is all that is need, really. A-poc is REALLY one of the most over rated characters EVER. He would lose to a local police precinct.