Minecraft wiki entry for Bubble_Column, associated text: A whirlpool, or downward bubble column, is the most common type that generates in the Overworld, often originating from magma at the bottom of underwater canyons. A whirlpool can be identified by the presence of air bubbles wandering downward. They drag entities downward. A boat ridden over a whirlpool shakes and eventually sinks if kept above the whirlpool for too long.