What type of vegetable has a dark root with hot sharp taste?

The vegetable you're describing is likely horseradish.

Here's why:

* Dark Root: Horseradish has a long, thick root that is dark brown in color.

* Hot, Sharp Taste: Horseradish is known for its intensely spicy and pungent flavor, which comes from its high concentration of allyl isothiocyanate, a volatile oil that stimulates the taste buds.

Let me know if you'd like to know more about horseradish!