Minecraft wiki entry for Combat, associated text: Guardians are difficult to attack with melee attacks when underwater, as the player will not be able to quickly approach the guardian due to the slowing effect of the water and the fact guardians will swim away when approached by a player it is targeting. The guardian will deal around 2 damage every time it is hit when its spikes are extended. If cornered, the guardian will usually extend its spikes and fire its laser at the player, even at point-blank range.