I found animation error in Bakugan Gundalian invaders episode 21,in this episode at the beggining Drago is Pyrus Helix Dragonoid,and not Pyrus Lumino Dragonoid that is the drago he was in previous
Bakugan Battle Brawlers 31. A Place Far From Home - video Dailymotion
Bakugan Battle Brawlers | Bakugan Toys | All Things Bakugan » New Bakugan Episode – Mechtanium Surge Episode 31: Combination Impossible