Palkia

In The Battle Finale of Legend!, Palkia and Dialga were summoned by Cyrus on the Spear Pillar. They were put under his control through the use of the Red Chain and were tasked by him to open a portal to another dimension, wanting a world of his own. After the Red Chain's destruction and Cyrus's exit, Palkia and Dialga rampaged, creating a danger for Sinnoh.

Lol text took by bulbapedia credit them

Type: Water and Dragon

Did you know that: Sinnoh? more like winnoh! ha!