I'm continuing the regi pokemon because I've already done two.

Regice gets a new (made up) ability called mega Scope, which improves the accuracy and boosts the power of beam and cannon moves. This boosts some of its moves like Zap cannon, ice beam, and hyper beam. It gets a huge sp attack boost as well as small defensive boosts. This Regi gets large ice cannons instead of claws on the ends of its arms. There is also a frigid air around it that helps cushion attacks and it gets spikier armor.
Stat boosts:
70 sp attack
20 sp defense
20 defense
-10 speed