Earth Key is a Key Item in Bug Fables. It is given to Team Snakemouth by Astotheles after his defeat during the events of Chapter 4. It is combined with the Heaven Key to create the Sandcastle Key.

Key Items
Ancient Castle Key	Ant Compass	Ant Doll
ATK Potion	Bad Book	Bed Bug
Bee Hat	Big Ancient Key	Big Crank
Big Crank Bottom Half	Big Crank Top Half	Big Gear
Blackest Paint	Blank Card	Bond Berry
Bug Ranger Plushie	Card Trophy	Chomper Seed
Coal Crystal	Crimson Ore	Crystal Crown
Crystal Fang	Crystal Feather	Crystal Fruit
DEF Potion	Desert Key	Dotted Ball
Drowsy Ribbon	Earth Key	Eastern Doll
Explorer Permit	Factory Pass	Flower Key
Heart Berry	Heaven Key	History Book
HP Potion	Iron Seed	Lab Card
Leaf Umbrella	Lore Book	Map of Bugaria
Mechanical Claw	Medium Gear	Moon Offering
Mothiva Doll	MP Potion	Mysterious Piece
Orange Horn	Overdue Book	Package
Peculiar Gem	Platinum Card	Pretty Ribbon
Prison Key	Red Paint	Root Cloth
Rusty Key	Sand Castle Key	Shady Note
Shocking Ribbon	Small Gear	Sophie Petal
Stolen Silk	Sun Offering	Super HP Potion
Super Pepper	Super TP Potion	Team Ribbon
Top Hat	TP Potion	Venom Ribbon
Wasp Key	Wrapped Lunch	Wooden Crank