Stray Demon

The  is an optional boss found by returning to the Undead Asylum.

The Stray Demon is similar to the Asylum Demon from the game tutorial, but is far more powerful. Among other things, it is no longer susceptible to Black Firebombs.

The Stray Demon is fought by falling through the floor in the middle of the room that had housed the Asylum Demon.

Strategy
The player will first fall through the floor, lose some health from the landing, and end up across the room in front of the Stray Demon.

Casting Fall Control before the fight will negate the damage players suffer from falling into the Stray Demon's pit.

As much of the fight as possible should be spent at a distance of a few yards behind the demon, because his area of effect attacks can reach behind him a short distance. In between his explosion attacks, players should pelt his rear with their attack of choice.

The demon will occasionally fly into the air and perform a hip drop. When this occurs, walking around to his left will avoid all the damage, but will cause a knockdown if the player is close enough to him, or deal heavy stamina damage if keeping the shield up. If sticking to his right instead, his weapon, along with his own body, will damage and knockdown the player.

There is no place to use the White Sign Soapstone in this area so it's not possible to summon others for this fight.

The Stray Demon is susceptible to bleed damage. Weapons like the Bandit's Knife and the Uchigatana are thus more effective against him.

The Demon can be inflicted with both Toxic and Poison.

Double Hammer Swing
Two horizontal swings of the Demon's hammer. Similar to the Asylum Demon's attack. Can be blocked, but heavy stamina drain occurs. Can also be rolled under, allowing the player to attack the Demon.

Power Smash
An overhead hammer smash. Can be avoided by dodging to the left or right.

Double Power Smash
Can only be used after the first Power Smash. The Stray Demon raises its hammer, then smashes it down again. Can be dodged by rolling to the left or right.

Butt Slam
The Stray Demon flys up, pause momentarily, then falls to the ground.

Flame Explosion
The Stray Demon swings its arm outwards, then causes a massive explosion in front of it. Unlike the Hammer Drive attack, it doesn't have any backwards hitbox and can be dodged by getting behind, or even under, the demon. Despite the attacks name, it deals purely Magic damage.

Hammer Drive Explosion
Similar to the Asylum Demon's attack, however, once the hammer hits the ground, a massive explosion occurs at the point of impact. Telegraphed well by the Stray Demon raising its hammer, and can be dodged.

Trivia

 * When first starting the game and exiting the prison cell, the Stray Demon can be seen wandering around his boss arena through the bars to the right, although he can't be interacted with at all.