Minecraft wiki entry for Drowned, associated text: Drowned use a swimming animation similar to the player. They use this animation whenever they try to pathfind to a player that is either below or above them; if the player is on the same ground level, the drowned simply walk toward them. Drowned also use this animation if they are tracking a player while they are not standing on a solid block. Their hitbox does not change when using this animation. Also, if they hold a nautilus shell or anything else in their offhand, their arms are in the same posture as a player's. When attacking, they use the player's attacking animation. Still, they use the same swimming animation when tracking a player underwater.