Gyarados-Mega @ Gyaradosite
Ability: Intimidate
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Waterfall
- Crunch
- Dragon Dance
- Protect

can also go with an adamant nature - up to you. jolly outspeeds up to base 145s at +1 (the relevant mega bee) but doesnt hit 150s or 151s (deo and mosa) adamant outspeeds shaymin sky but not base 130s like crobat, and with adamant you are slower than jolly breloom or bisharp without a boost