When used by any character other than Tainted Eve, removes half a heart of health upon use and creates a Clot familiar.
Blood clot familiars mimic Isaac's movement (including flight), firing, and tear effects.
Blood clot familiars will mimic all tear-altering effects, such as Spirit Sword.
Holding down the swap button allows Isaac to move independently from the blood clots.
The familiars have health and will be destroyed if they take enough damage. They start with a set amount of HP when spawned, and the health of Red Heart and Rotten Heart Clots will slowly decay down to 1 HP over time, while the health of the other clot types decay down to 5 HP.
Their health decays at a rate of 1 HP per 2.5 seconds.
Passively, holding down the fire button will create blood clot familiars every two seconds and drain half a heart.
Upon activation, Sumptorium destroys any remaining blood clots and heals Tainted Eve for the same type of hearts that were used to generate them. The blood clots deal 3x Tainted Eve's damage to enemies they pass through as they return.
Should Tainted Eve have more blood clots than room in her health bar when doing this, all excess blood clots will drop next to her.
The charge time is only 1 second rather than 10 seconds.
Clots from a previous run will carry over during a RERUN.
Sumptorium can't spawn more than 64 clots at once.
This limit is shared with blue flies and blue spiders. If there are multiple flies, spiders and clots on the screen at the same time, the limit will be 32 for the clots and 32 for the flies/spiders.
Sumptorium cannot absorb more than 29 clots at once.
Activating Sumptorium does not restore Tainted Eve's health immediately, as it is not restored until the recalled blood clots return to Eve.
If Isaac obtains flight, the clots will hover instead of moving across the floor.
Glowing Hourglass: Each use of Glowing Hourglass that does not move Isaac to a different room than the one he is currently in (such as the starting room of a new floor) will duplicate the clots. (This is possibly a bug)
Book of Virtues: For Tainted Eve, it will create red wisps for every clot consumed, and they will disappear if she starts creating clots again. Soul charges cannot be used to create wisps. Has no effect for other characters.
Car Battery: Summons 2 clots instead of one for double the health cost. Not Recommended forTainted Keeper as it can instantly kill him.
The Forgotten: In order to stop clots from moving while playing as The Forgotten, it is needed to hold down Left CTRL/RT while switching to The Soul, and vice-versa.
The Lost/Tainted Lost: Sumptorium spawns a blue clot and kills The Lost and Tainted Lost immediately upon use.
My Reflection: Clots' tears will be redirected to Isaac instead of returning back to them.
Strawman: Clots will follow Strawman instead of Isaac if they were spawned in a previous room.
Tainted Eden: Clots made by Sumptorium are retained after taking damage.
Tainted Forgotten: Clots made by Sumptorium have a club too, but they are commanded by Tainted Soul, making it the only way to attack while moving freely.
Tractor Beam: Clots' tears will be fired from Isaac instead, and will stay within the tractor beam.
Alabaster Box: Sumptorium can create clots by using hearts inside the box. It prioritizes hearts inside the box instead of using Eve's soul or black hearts.
Lil Clot: The clot spawned by this trinket is its own separate clot variant although it functions the same as the red one. As such, it cannot be absorbed by Sumptorium.
Maggy's Bow: Does not provide additional healing when absorbing clots.
A Sumptorium is a metal drinking straw used in the Roman Rite to receive the Blood of Christ in Holy Communion.
Even though Tainted Eve wields a Sumptorium-like weapon when left on half a heart and all blood clots are destroyed, this is not an effect given by the Sumptorium item itself and is a character-specific trait.
Tainted Eve, removes half a heart of health upon use and creates a Clot familiar.
Spirit Sword.
Red Heart and 
Rotten Heart Clots will slowly decay down to 1 HP over time, while the health of the other clot types decay down to 5 HP.
Fire Places, and lasers.
Bombs and 
Troll Bombs deal 2 points of damage.
Dark Matter
Sacred Heart
Midas' Touch (scales with luck)
Compound Fracture
Gold Hearts, 
Eternal Hearts, 
Soul Hearts, 
Black Hearts, or 
Bone Hearts.
Baby-Bender: Gives the clots homing shots.
BFFS!: Doubles the clots' size and damage.
Forgotten Lullaby: Increases the clots' fire rate.
Glowing Hourglass: Each use of Glowing Hourglass that does not move Isaac to a different room than the one he is currently in (such as the starting room of a new floor) will duplicate the clots. (This is possibly a bug)
Sacrificial Altar: Turns each clot into a penny.
Spin to Win: Makes the clots deal 6 contact damage.
The Ludovico Technique: Spawns a controllable Ludo tear for each clot.
A Lump of Coal: Each Ludo tear's damage is based off of the distance from its corresponding clot.
Book of Virtues: For Tainted Eve, it will create red wisps for every clot consumed, and they will disappear if she starts creating clots again. Soul charges cannot be used to create wisps. Has no effect for other characters.
Box of Friends: Cannot be used to duplicate clots.
Car Battery: Summons 2 clots instead of one for double the health cost. Not Recommended for 
Tainted Keeper as it can instantly kill him.
The Forgotten: In order to stop clots from moving while playing as 
The Soul, and vice-versa.
Keeper/ 
Lazarus/Revival Items: Clots will be retained after losing the extra life.
The Lost/ 
Tainted Lost: Sumptorium spawns a blue clot and kills The Lost and Tainted Lost immediately upon use.
My Reflection: Clots' tears will be redirected to Isaac instead of returning back to them.
Strawman: Clots will follow Strawman instead of Isaac if they were spawned in a previous room.
Tainted Eden: Clots made by Sumptorium are retained after taking damage.
Tainted Forgotten: Clots made by Sumptorium have a club too, but they are commanded by 
Tainted Soul, making it the only way to attack while moving freely.
Tractor Beam: Clots' tears will be fired from Isaac instead, and will stay within the tractor beam.
Alabaster Box: Sumptorium can create clots by using hearts inside the box. It prioritizes hearts inside the box instead of using Eve's soul or black hearts.
Lil Clot: The clot spawned by this trinket is its own separate clot variant although it functions the same as the red one. As such, it cannot be absorbed by Sumptorium.
Maggy's Bow: Does not provide additional healing when absorbing clots.
Tainted Eve Unlocks 
Delirium Unlocks 
The Binding of Isaac: Rebirth
