LIKE I SAID, MY TERRAKION IS ALSO SCARFED. and you can't lock yourself into a move cuz terrakion-gengar resist your stabs, its gonna be a prediction game from then on. on the other hand, all of your pokes die to a CC from MY terrakion.
what matters is not the gastro per se, but the fact that i had to lose landorus to kill it. nothing on your team can take on landorus except for azelf, which would quickly die from switching in and out, life orb, and sandstorm.