I can see fun ideas in this one and I think it got potencial however there are a few things I would like to change. As it is now it's a forced combo to water and earth which means not many different decks are viable. Then only ones I can think of is nymph tears, maybe rush( maybe ) and some sop otk combo.
Well is mud ball going to be a card in the game too or is it just Pile of earth? If it is I think it deserves a cost increase if not I think it deserves a buff.
1: Make big and small earth pile have the same playing quanta cost, would make things easier.
2: Make the base damage to either 4 or 5 in both the upped and un upped one.
3: Make it include attack too.
4: Make it include all your none airborne creatures or something like that.(removes cards like titan and dragons from this)
And now I think you have a perfectly balanced and fun card to play. YOu could make fun trios and good bows.
Thanks for your comment
Well, Mud Ball is not intented to be available in the bazaar. It's like Malignant Cell and Shard Golem, you can obtain it only from Pile of Earth.
Yeah, I'm thinking about buffing it to HP/4 in unupped and HP/3 in upped.
And I would like to stick to earth and water = you need only these to make mud ;]
Ghost of the Past also has a forced combo, so I think it's fine