During the day the werewolf is in a human form dressed in ragged clothing. It occasionally shouts "Help me!". When they are hit, they yell or say, "You're hurting me. Stop it!" and will not attack in return. Despite being in human form during the day, hostile mobs- such as those found in caves- will not attack them.
At night, the human appears as if it is taking damage for around 3 seconds, before transforming into a humanoid wolf with a puff of smoke and even though there would hurt you he doesn't hurt you
. They can be easily harmed with gold tools - other weapons will hurt them, but take much longer. Even the most powerful 'sword' in the game, the Red Katar, takes 40+ hits it.
Werewolves have the ability to sprint while walking on four legs. They also are able to move very fast upon chasing the player onto ice. This is useful if being pursued because the werewolf will slide very far away, making them no longer a threat, as long as you can shuffle around to avoid them. Alternative methods of killing a werewolf include fire, lava, drowning (rare, but possible), suffocation in sand or gravel, explosions (caused by TNT, creepers, nuclear bombs or a nuclear meltdown), uninsulated but powered IC wires, Tesla Coils, cacti, and long falls.
The human form can drop sticks and wooden tools, while the werewolf form can drop stone and iron tools, and occasionally a golden apple.