Gives Isaac a 33% chance to visually turn into Azazel when clearing a room. Isaac keeps his hearts and items, but changes his tears to be a short range Brimstone, gains a x1.5 damage multiplier, a Speed increase, and the ability to fly.
The effect lasts until clearing and leaving another room.
The effect can be taken to the next floor.
The Speed increase is equal to the difference between the current character's base speed and Azazel's (which is 1.25). For instance, Keeper will gain +0.35 Speed since his base speed is 0.9.
Notes
Dropping the trinket after this transformation will not reverse it until a new room is cleared.
The trinket only changes Isaac's appearance to be as Azazel's but doesn't change the actual character. This means that the trinket cannot be used to unlock achievements for Azazel.
The effect will not change Isaac's health mechanics. For example, The Lost will retain his zero health and Holy Mantle.
When entering the area in Mines / Ashpit to obtain Knife Piece 2 while in the Azazel form, flight and the Brimstone laser will remain despite visually reverting.
However, because picking up the Knife Piece triggers a room clear, the form will be reverted upon leaving the knife piece room, and the escape sequence will not benefit form the trinket's effect.
Synergies
Golden Trinket / Mom's Box / multiple copies: One boost or additional copy increases the chance of Isaac turning into Azazel to 50%. Further boosts or copies increase the chance to 100%.
Rock Bottom: Isaac retains the damage multiplier and base speed increase after the effect ends. Also removes the tear delay multiplier when transformed into Azazel.
Interactions
Azazel: Increases the width of his Brimstone, identical to his Birthright effect.
Birthright as Azazel: Azazel's Stump has no further effect.
The Forgotten: Still uses his regular bone club attack while in skeleton form. The Soul will work as expected, and use the short-range Brimstone.
Tainted Forgotten: The bone pile will visually turn into Azazel, with no gameplay effects.
Azazel when clearing a room. Isaac keeps his hearts and items, but changes his tears to be a short range 
Brimstone, gains a x1.5 damage multiplier, a Speed increase, and the ability to fly.
Keeper will gain +0.35 Speed since his base speed is 0.9.
The Lost will retain his zero health and 
Holy Mantle.
Mines / 
Ashpit to obtain 
Knife Piece 2 while in the Azazel form, flight and the Brimstone laser will remain despite visually reverting.
Golden Trinket / 
Mom's Box / multiple copies: One boost or additional copy increases the chance of Isaac turning into Azazel to 50%. Further boosts or copies increase the chance to 100%.
Rock Bottom: Isaac retains the damage multiplier and base speed increase after the effect ends. Also removes the tear delay multiplier when transformed into Azazel.
Birthright effect.
The Forgotten: Still uses his regular bone club attack while in skeleton form. The Soul will work as expected, and use the short-range Brimstone.
Tainted Forgotten: The bone pile will visually turn into Azazel, with no gameplay effects.
Tainted Azazel Unlocks 
Mother Unlocks 
The Binding of Isaac: Rebirth
