What kills drowned?

What kills drowned? This gives a drowned 20 health points (because 1 heart = 2 health points). To kill a drowned, you need to inflict 20 points of damage to the drowned.

This gives a drowned 20 health points (because 1 heart = 2 health points). To kill a drowned, you need to inflict 20 points of damage to the drowned.