Tyranitar @ Leftovers / Tyranitarite
Ability: Sand Stream
EVs: 252 HP / 28 Def / 228 SpD
Careful Nature
- Curse
- Crunch / Stone Edge
- Rest
- Sleep Talk / Fire Punch
This is an old DPP set but it can still put in work in SM.
Tyranitar's high Special Defense in sand makes it an effective Curse user, as it patches up its already respectable Defense and also boosts its Attack to dangerous levels. Rest and Leftovers provide longevity, which allows Tyranitar to set up more and potentially win the game. Rest also means Tyranitar is able to shake off any status, which means it can comfortably set up on the likes of Toxapex, Chansey and even Rotom-Wash and Heatran. Crunch is reliable STAB that hits everything. Sleep Talk is the preferred choice for the final moveslot as it avoids Tyranitar from being helpless for two turns every time it uses Rest. However, Fire Punch is an option to hurt all the Steel-types that want to come in, like Kartana, Scizor, Ferrothorn, Celesteela, Magearna and Mawile. If you use Fire Punch, Stone Edge is preferred over Crunch as it hits harder and Fire Punch means you wouldn't be walled by Steel-types anymore.
The Mega stone can be used as it notably boosts its Attack and Defense to even higher levels, but it loses out on passive recovery and takes up the Mega slot, which is why Leftovers are usually preferred.
The spread is to allow non-Mega Tyranitar to survive the OHKO from Kartana's Leaf Blade without any Curse boosts and potentially OHKO it back with Fire Punch, while maximizing its Special Defense which allows it to survive Mega Alakazam's Focus Blast and OHKO it back with Crunch.