“This may control the polarity of the whole universe.”
“It contains a vital spark.”
“THIS WOULD PROBABLY BLOW MY CIRCUITS”
“This is a box full of sadness and woe.”
“Ah yes! This is exactly what I need.”
“Perhaps this hölds the secret tö this land's Bifröst.”
“The power in this box is unimaginable.”
“This looks important.”
“"This" likely connects to a "that."”
“A simple pirate like me ain't be knowin' whut this be fer.”
“It does something. Probably.”
The Box Thing is an Item and one of four Things used on the Wooden Thing to travel to the next world. It spawns naturally in every world in its own Set Piece. It is surrounded by Stone Walls and Evil Flowers along with a Gnome and Spear on a small patch of Rocky Turf.
There are two version of it, one that spawns in Survival Mode and one in Adventure Mode, that differ from their color schemes. Players can craft a Divining Rod to help them track the Box Thing.
The only purpose of the Box Thing is to be used on the Wooden Thing. It's an important gameplay Item and as such it cannot be destroyed or stolen by Mobs, e.g. Krampus or Splumonkeys.