What are all Pokemon that lose stats upon mega evolution?

Question

eg: Sableye losing speed, Diancie losing defense and special defence, Beedrill losing special attack.

Answer 1

• Mega Beedrill (45 SpA - 15 SpA)
• Mega Mewtwo Y (90 Def - 70 Def)
• Mega Ampharos (55 Spe - 45 Spe)
• Mega Heracross (85 Spe - 75 Spe)
• Mega Sableye (50 Spe - 20 Spe)
• Mega Camerupt (40 Spe - 20 Spe)
• Mega Garchomp (102 Spe - 92 Spe)
• Mega Abomasnow (60 Spe - 30 Spe)
• Mega Diancie (150 Def - 110 Def)

Source: Pokemondb's stat pages, and this

That's all!
SeeYaLater!

Comments

necropost, but mega diancie loses 50 points in special defense too :P

Answer 2

Beedrill SpA: 45 to 15
Mewtwo Y Def: 90 to 70
Diancie Def and SpD: 150 to 110

The rest of these have lower speed.
Ampharos: 55 to 45
Heracross: 85 to 75
Sableye: 50 to 20
Camerupt: 40 to 20
Garchomp: 102 to 92
Abomasnow: 60 to 30
source