Haven't dropped anything here for a while...
Now that that's out of the way... random pokemon time.
...Gigalith, it would seem.
MEGA GIGALITH
Design: Gigalith's crystals grow out and spread in extreme proportions, concealing most of its form, and weighing it down to the ground, making it nearly immobile.
Type: Rock, what else. Crystals != Fairy. (Diamond Storm, Power gem)
Ability: Unaware (...Assuming it can still see, in the first place. I'd like a slight accuracy debuff on GigaGigalith, for the same reason)
Stats:
85 --> 85
135--> 140
130--> 160
60 --> 85
80 --> 140
25 --> 5
(Yes, I really did just lower its speed to raise its Satk. Which it won't use.)
Monstrous defenses, rock type further boosts its absurd SDef in Sandstorm, and setup can't phase it. However, if you hit hard enough by default, it'll still die, easy enough. Better do it fast, since this thing can and will toxistall your team on its own.
252 SpA Life Orb Lucario Focus Blast vs. 252 HP / 4+ SpD Gigalith in Sand: 213-252 (56.9 - 67.3%) -- guaranteed 2HKO
Okay, maybe a bit powerful, but no good recovery, outside of Rest. Cros your fingers, and hope you deal 76% damage so it can't sub, I guess!
Still dies in one hit to MM Raycraycray
Edit: What if M-Blissey with +100 Defense, tho.