Zygarde as a physically defensive pokemon is flat out amazing with hazard support, 252 HP, 252 Def, EQ, Dragon tail, Rest and Sleep talk.
You absorb status like nobodies business, and take hits like a champ, the only thing remotely concerning is ice attacks, but they are generally lived through unless special. Its base speed is also useful as a defensive pokemon, getting sleep talk dragon tails off with decent speed is annoying for opponents. Bisharp? Darmanitan? Hell, even Mega Heracross can't 2HKO (although, he will bring you close).
If teams aren't prepared, or you take out the one threat, you can just keep dragon tailing and resting up. Seriously, shove Deoxys-D (or any hazard setter) with defensive Zygarde and watch the magic.
You absorb status like nobodies business, and take hits like a champ, the only thing remotely concerning is ice attacks, but they are generally lived through unless special. Its base speed is also useful as a defensive pokemon, getting sleep talk dragon tails off with decent speed is annoying for opponents. Bisharp? Darmanitan? Hell, even Mega Heracross can't 2HKO (although, he will bring you close).
If teams aren't prepared, or you take out the one threat, you can just keep dragon tailing and resting up. Seriously, shove Deoxys-D (or any hazard setter) with defensive Zygarde and watch the magic.