Decidueye

Base stats, and where each one ranks among the 234 Pokémon legal in Regulation M-B.
Stat	Base	Rank
HP	78	118th
Attack	107	73rd
Defense	75	154th
Sp. Atk	100	81st
Sp. Def	100	51st
Speed	70	144th
Total	530	49th

Legal, but nobody plays it

Decidueye is legal in Regulation M-B and did not appear often enough on the ladder to produce usage statistics. It is legal and simply out of favour, which makes it unmeasured rather than unusable.

The Pokémon itself

Decidueye is number 724 in the National Dex, a Alola Pokémon, Grass and Ghost with a base stat total of 530 — 49th of the 234 Pokémon legal in this regulation. Its best stat is Attack at 107, 73rd in the format; its weakest is Speed at 70, 144th. It can have Overgrow and Long Reach. The Champions module tiers it UU.

It sits in a 3-stage line: Rowlet → Dartrix → Decidueye. Not all of that line is legal in this regulation — Rowlet and Dartrix are not.

What gets through

As Grass and Ghost, 5 of the eighteen attacking types do extra damage to it. It resists 4 and is immune to 2. The board above has all of it. 6 other legal Pokémon share the same typing and the same board: Sinistcha, Gourgeist-Large, Trevenant, Gourgeist-Super, Gourgeist and others.

What threatens it

Smogon publishes no head-to-head checks-and-counters data for doubles formats, so this list is computed, not measured: the most-played Regulation M-B Pokémon carrying a damaging move of a type Decidueye takes extra damage from.

Kingambit — Sucker Punch (Dark, ×2), on 99.8% of its sets
Incineroar — Flare Blitz (Fire, ×2), on 91.2% of its sets
Charizard-Mega-Y — Heat Wave (Fire, ×2), on 99.2% of its sets
Basculegion — Last Respects (Ghost, ×2), on 99.9% of its sets
Pelipper — Hurricane (Flying, ×2), on 98.1% of its sets
Staraptor-Mega — Brave Bird (Flying, ×2), on 83.4% of its sets

Against its own formes

Decidueye has 2 legal formes in this regulation and they share a typing, so the only thing separating them is the stat line. This one has the highest Sp. Atk at 100, Sp. Def at 100 and Speed at 70 of the 2. It has the lowest HP at 78, Attack at 107 and Defense at 75. The others are Decidueye-Hisui.

Speed and weight

At level 50 with a boosting nature and full investment, Decidueye reaches 134 Speed; left uninvested with a neutral nature it sits at 90. Invested, it outruns 6 of the 20 most-used Pokémon in the regulation when they are invested too — which is the comparison that decides who moves first.

It weighs 36.6 kg, so Grass Knot and Low Kick hit it for 60 base power. That is a real consideration in a format where both are common.

Its move pool

Decidueye learns 96 moves in the Champions data. 56 of them do damage, across 10 of the eighteen types, and 24 share a type with it and so get the same-type bonus. Its hardest-hitting same-type move is Frenzy Plant at 150 base power. It also has priority: Sucker Punch at +1 and Shadow Sneak at +1.

That pool is what the team builder reads from when you seat it, and the damage calculator will take it as the attacker with the form already chosen.

Taking damage

Dealing damage