Rating: 8/10. acid spray, snarl, and chilling water support needed. Build details in description.
Meganium @ Covert Cloak
Ability: Overgrow
Tera Type: Grass
EVs: 252 HP / 252 SpA
Modest Nature
– Grass Knot
– Giga Drain
– Reflect
– Light Screen
Vitamins: 25 HP Up (or Health Mochi), 25 Calcium (or Genius Mochi)
Feathers: 2 Health Feathers, 2 Genius Feathers
Stats at lvl 100 w/ perfect IVs:
HP : 364
Defense : 236
Sp.Atk .: 291
Sp.Def. : 236
Speed : 196
Support Requirements : special defense debuff through shield (acid spray), attack debuff through shield (chilling water), and special attack debuff through shield (snarl).
Example Supporter: https://www.youtube.com/watch?v=1Vzpg6O6v7w
Strategy: light screen (optionally renewing 1-2 times when it expires). reflect (optionally renewing 1-2 times when it expires). 3x giga drain. terastalize. giga drain when you need HP. grass knot to victory.
Notes: a physical build doesn’t need acid spray so it can be supported by a wider range of supporters, but it needs a shell bell, healing support, or synthesis. charm or curse can replace reflect, light screen, or grass knot, reducing the need for chilling water support. with adequate support, you can reduce use of screens from 3 each to 2 or 1 each, or none at all. you’ll take more damage but speed up the run. bulldoze or trailblaze can be used to outspeed. mud-slap is worth considering too.
Pros: supereffective tera type matching base type, great HP stat, decent defense and special defense stats, excellent special attack stat. resists earthquake, earth power, and wood hammer. no weaknesses. reflect and light screen halve damage from physical and special attacks respectively for 4-5 turns. grass knot and giga drain have 100 accuracy and deal supereffective STAB (tera-boosted when terastalized) damage. grass knot has 120 base power due to torterra’s heavy weight. giga drain heals 50% of damage dealt. covert cloak prevents special defense debuffs from earth power. overgrow gives 1.5x damage boost when HP is below 1/3rd.
Cons: outsped by torterra