Stadium/Terra Cup/5

Reward:  2 and 25000

Strategy: Use this dragons:Petroleum Dragon level 30,Cool Fire lv30, and Gummy lv30.

Use first Gummy with Poison Ivy to lower Waterfall's HP. Use Cool Fire with Snow Storm to defeat Waterfall.Finally   use Petroleum with his strongest water attack to defeat both Chameleon and Cactus

Or, you can use rare hybrid dragons like Cool Fire (not for waterfall and chameleon), Soccer and Armadillo (This will be a hard fight if your dragons aren't at least lv20 and ranked up with stars).