Pokemon-ish Mobile Game?

If i remember well it was a little bit like Pokemon, you could catch little creatures and then use them to stun and capture more. There were some other things, too. The creatures were found in various "Planets" that you could explore, but to find a new planet you needed to fight a boss. If you had two creatures of the same type you could combine them to make another one * . The graphics were pretty cool, they were pixelized. The icon of the app was a close-up of an blue monster smiling, and i think i played this on an IPhone * .


The sentences marked with * are things i'm not completely sure about.