In the Dungeons & Dragons fantasy role-playing game, an ooze is a type of creature. This category includes such monsters as slimes, jellies, deadly puddings, and similar mindless, amorphous blobs. They can be used by Dungeon Masters as enemies or allies of the player characters.
Many oozes dwell underground, and most secrete an acid from their skin that dissolves flesh and other materials rapidly. Oozes are essentially blind, but more than make up for that with an ability called "blindsight", which allows them to discern nearby objects and creatures without needing to see them visually.
The appearance of Slimes in the Shin Megami Tensei series are stated to be the result of incomplete, faulty summons of demons. It comes as no surprise that Mara resembles a Slime in its botched summoning form.
"A primitive monster with a body of jelly-like, viscous liquid. They have no body parts per se, but rather possess an inorganic structure like liquid metal. They can create their own body parts as necessary and sometimes even mimic other types of creatures. Their mysterious, jelly-like bodies are very resistant to physical attacks. One theory holds that they are what results when the computer tries to summon another type of demon and fails."
—Shin Megami Tensei IMAGINE Compendium
Slime is the first demon you fight in Second Home and is among the Virtual Battle tutorial mobs. It can be contracted in Ueno during the day, Suginami Tunnels bronze/silver/grey instances, Shibuya's Celu Tower bronze, and Old Ichigaya Camp's bronze and silver instances. It appears as one of the bosses within DB Watanabe and DB Saitou's hacked chip instances. It is common to see players raising the inexperienced variant as a quick means of acquiring the skill Megidoraon.
"The product of a failed summoning. Bereft of its original powers, it's trapped in an incomplete gel form. Its journey from the Atziluth world to the Assiah world was incomplete in some way."
—Shin Megami Tensei: Strange Journey Compendium
Slime is the first demon that appears and assaults the Red Sprite in the game. The protagonist initially fends them off as Unknowns on the deck and removes them while they are infesting the Sickbay afterward. From then on they appear as random encounter enemies in the beginning areas of Sector Antlia.
"The byproduct of a failed summoning. Devoid of its original powers, it's trapped in an incomplete gel form. Its journey from the Atziluth world to the Assiah world was incomplete in some way."
—Shin Megami Tensei IV: Apocalypse compendium
Slime appears accompanied by Legion in the Kinshicho south exit shopping district. While weak, it still grants the Lunge skill and Life Drain skills if they are desired. Or it can be used as fusion fodder.
The Slime appears as the only demon of the Foul race, which can only be faced during a full moon or new moon. It can't be used in battle, but has a essential purpose in fusion: fusing a Slime with any demon will result into a random demon, that varies according with how many times you try to combine it. If you combine the Slime with the same demon twice, the second result will be different from the first. But fusing it during a full moon, will create a determined Shin Akuma race demon.