Board Thread:Quests and Special Events/@comment-24562513-20140219153953/@comment-11259553-20140220114749

The number of hammers you have determines which dragon you will face. If you spend Hammers to uncover a pane, you'll "go back" to the earlier dragons.

0 - Viking

1 - Poo

2 - Firebird

Since you only need 3 Hammers to uncover a pane you can do the entire Hammer line fighting these 3 over and over. If you want you can save up and fight the full lineup of dragons ... but I wouldn't recommend it since if you crash you can be set back to 3 Hammers. I saved up to 12 to see the line of dragons for my site ... crashed when I tried with 12 Hammers (normally you wouldn't need to fight then, so maybe it's always going to crash?), and was set back to 3... wasting the 18 Gems I had rushed the fights with.