#0308 · Gen 3

Medicham (Mega) — Best counters

Weaknesses

	Pokémon	Fast move	Charged move	Weather	Score
1	Gengar (Mega)	ghostLickELITE	ghostShadow Ball	Fog	10013.0
2	Rayquaza (Mega)	flyingAir Slash	flyingHurricaneELITE	Windy	9412.2
3	Pidgeot (Mega)	flyingGustELITE	flyingBrave Bird	Windy	8811.4
4	Gardevoir (Mega)	fairyCharm	fairyDazzling Gleam	Overcast	8811.4
5	Enamorus (Incarnate)	fairyFairy Wind	flyingFly	Windy · partial	8711.3
6	Banette (Mega)	ghostHex	ghostShadow Ball	Fog	8711.3
7	Blacephalon	ghostAstonish	ghostShadow Ball	Fog	8511.1
8	Alakazam (Mega)	psychicPsycho Cut	ghostShadow Ball	Fog · partial	8010.4
9	Zacian (Crowned)	flyingAir Slash	fairyPlay Rough	Overcast · partial	7910.2
10	Enamorus (Therian)	fairyFairy Wind	flyingFly	Windy · partial	7810.1
11	Tornadus (Therian)	flyingGust	flyingBleakwind StormELITE	Windy	7810.1
12	Salamence (Mega)	dragonDragon Tail	flyingFly	Windy	7710.0
13	Chandelure	ghostHex	ghostShadow Ball	Fog	769.8
14	Gengar	ghostLickELITE	ghostShadow Ball	Fog	759.7
15	Yveltal	flyingGust	flyingOblivion WingELITE	Windy	749.6
16	Staraptor	flyingGustELITE	flyingBrave Bird	Windy	749.5
17	Tapu Lele	ghostAstonish	fairyNatures MadnessELITE	Overcast · partial	739.4
18	Zoroark (Hisui)	ghostShadow Claw	ghostShadow Ball	Fog	729.4
19	Dragapult	ghostAstonish	ghostShadow Ball	Fog	729.3
20	Blaziken (Mega)	fireFire Spin	flyingBrave Bird	Windy · partial	729.3

Medicham (Mega) is weak to Flying (×1.6), Ghost (×1.6), Fairy (×1.6).
Watch its Psychic/Fighting/Ice moves — counters like Gengar (Mega) and Rayquaza (Mega) take super-effective damage from them.
Fog weather boosts Ghost moves ×1.2 — the best time to battle Medicham (Mega).

Rankings are estimated cycle DPS (attack stat × move damage ÷ cycle time, with STAB and type effectiveness). Not a full battle simulation.