Guyot

A guyot is a big hump on the ocean floor that used to be a volcano! When a volcano erupts, it spits out hot magma (molten rock) from inside the Earth. After many, many eruptions, the volcano gets bigger and bigger, until it starts poking out of the water and becomes an island.

Over time, however, the volcano stops erupting and the magma cools and solidifies into hard rock. Then, the ocean water starts wearing away at the volcano, with waves and currents crashing against it. Eventually, the island sinks back down into the ocean, leaving behind a big, flat-topped mountain.

This mountain is what's called a guyot! It's shaped like a giant pancake, with a flat top and steep sides that go down into the ocean. The guyot is usually covered in different types of sediment and tiny creatures that live in the water, like corals and sponges.

So, in summary, a guyot is a big, flat-topped mountain on the ocean floor that used to be a volcano but sank back down into the water.