Regice

Regice looks like the ideal choice for a special wall; its massive base 200 Special Defense, usable HP, and access to support moves such as Thunder Wave and Gravity all look appealing. However, when you look closer you'll notice that it has weaknesses to common attacking types such as Fire-, Rock-, Steel-, and Fighting-type attacks, a crippling weakness to Stealth Rock, and a total lack of reliable recovery. With the correct support, Regice becomes an unequivocal special wall that can counter the likes of Rotom, Milotic, and Sceptile with ease, but just make sure to keep Regice away from super effective attacks and Stealth Rock.