Stalagmite

"Is this all real? Or has this been happening inside my head?"

The topic of this article is of a real-life subject that has been mentioned "in-universe" in a canon source. The Harry Potter Wiki is written from the perspective that all information presented in canon is true (e.g., Hogwarts really existed), and, as such, details contained in this article may differ from real world facts.

Potters'Vault — Stalagmites can be seen in this view of the Potters' vault at Gringotts Wizarding Bank

Harry Potter: "I never know. What's the difference between a stalagmite and a stalactite?"

Rubeus Hagrid: "Stalagmite's got an 'm' in it. An' don' ask me questions just now, I think I'm gonna be sick."

— Exchange between Harry Potter and Rubeus Hagrid while riding a Mine Cart to Vault 687^[src]

A stalagmite is a rocky formation that can be found on the floor of a cave. It rises from the floor of a limestone cave when mineralised solutions drip from the ceiling and deposits of calcium carbonate form columns on the ground. The corresponding formation on the ceiling of a cave is known as a stalactite.^[1]

There were huge stalagmites and stalactites by an underground lake in the Gringotts Wizarding Bank vault area.^[2]