The mysterious key you found in vtipoman's Treasure Box leads you into a sprawling outdoor/indoor space, populated by all sorts of creatures. Upon closer inspection, two main groups can be discerned...
The Final Outpost's Creatures – Growing (can use your clicks!):
The Final Outpost's Creatures – Grown (can sorta still use clicks):
Dragon Cave's Dragons – Growing (shouldn't really need extra clicks):
Dragon Cave's Dragons – Grown (don't need clicks):