The term for a cone-shaped feature on the floor of a cave that is formed by slow dripping water is a stalagmite.

Here's the breakdown:

* Stalagmite: A mineral deposit that grows upwards from the floor of a cave.

* Stalactite: A mineral deposit that hangs downwards from the ceiling of a cave.

Both stalactites and stalagmites are formed by the slow deposition of minerals from dripping water. Over time, these deposits can grow to impressive sizes.