Toxic Tangrowth
Tangrowth @ Leftovers
Ability: Regenerator
EVs: 248 HP / 212 Def / 48 SpD
Relaxed Nature
- Giga Drain
- Knock Off
-
Toxic
- Hidden Power Fire
Here we have Defensive Tangrowth, a pokemon that is weak on the special side and doesn't have room for Rock Slide or even Earthquake.
It is very easy to discover that this is the physically defensive set due to Leftovers, so Tornadus-T can think it is safe to enter on this thing on the switch.
Sleep Power has the problem of having a shaby accuracy (you will miss it a quarter of the times) and the presence of Tapu Koko as a top-tier pokemon, while the sleep clause exists and existed since many years that every team has a way to absorb a sleep without fearing too much.
I find Toxic much more reliable (you will miss it one every 10 attempts) because it puts a timer onto many targets that don't have reliable recovery or ways to get rid of this annoying status. Toxic is best paired alongside HP Fire, because the latter scares Steel-type pokemons to enter (bar Heatran).
Tornadus-T is difficult to trap in the traditional sense because it has a fast U-turn to escape from its checks and counters, plus Regenerator. Toxic also makes up for the loss of HP Ice because almost every 4x weak pokemon doesn't have reliable recovery (bar Gliscor).
Rock Slide has a 6,6% chance to 2HKO, but every Rock-weak pokemon is able to outspeed Tangrowth and hit it on the special side (Charizard-Y, Volcarona and other Flying types).
Luckily enough, the bird is weak to SR, so, with the aid of hazards and Toxic, Tornadus-T won't be able to heal off this combined damage and will die shortly after.
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