That's not a valid thing you can open. You can open a clue tier (Beginner, Easy, Medium, Hard, Elite, Master), or another non-clue thing (Birthday present, Casket, Crystal chest, Builders supply crate, Spoils of war, Bag full of gems, Mystery box, Nest box (empty), Nest box (ring), Nest box (seeds), Giant egg sac(full), Bronze HAM chest, Iron HAM chest, Silver HAM chest, Steel HAM chest, Casket, Crystal chest, Elven crystal chest, Grubby chest, Muddy chest, Ogre coffin, Sinister chest, Brimstone chest, Larran's chest, Seed pack, Baby impling jar, Young impling, Gourmet impling, Earth impling, Essence impling, Eclectic impling, Nature impling, Magpie impling, Ninja impling, Crystal impling, Dragon impling, Lucky impling)