Mourning Wood

Mourning Wood is a hardmode miniboss encountered during the mid-to-final waves of the Pumpkin Moon.

During combat, the Mourning Wood alternates between firing a volley of flaming spikes straight at the player that pass through blocks, and firing a jet of spark-like flames  that are affected by gravity as well as being stopped by blocks and they stay on the ground for a while, doing damage to players that touch them. This can be frustrating while fending off other enemies, but using a flight accessory helps immensely, as the flames aren't too accurate to the player's location. Also if you have 2 Mourning Woods at a time you may have to dodge both attacks which can be again frustrating.

Tips

 * Floats through blocks to reach the target player, resembling Wraith's behavior, but otherwise walks on surfaces and cannot jump.
 * Due to this it's perfectly capable of fitting into spaces much less than its size.
 * They do not despawn after killing all available players. This, combined with their high damage potential and ability to phase through solid blocks, means that an unprepared player can easily spend most of the night being spawn-camped by one or more Mourning Woods. Making a bed in or above your intended arena, with space to start moving as soon as you respawn, is essential to avoid getting trapped and killed repeatedly.
 * They appear to be immune to most debuffs, however they are vulnerable to the Ichor debuff.
 * Pay attention to when a Mourning Wood stops walking - this means it's going to attack.

Trivia

 * The Frost Moon counterpart of the Mourning Wood is the Everscream.
 * "Morning wood" is one of several similar slang or colloquial terms referring to the phenomenon of nocturnal penile tumescence (erection) during and immediately following sleep.