The Blob was an independently made American horror/science-fiction film from 1958 that depicts a giant amoeba-like alien that terrorizes the small community of Phoenixville, Pennsylvania. Today, the film is recognized as one of the quintessential 1950s American sci-fi/horror films.
"An infamous jelly-like monster. It swallows humans and grows. It is said that the only way to stop blobs is to freeze them."
—Shin Megami Tensei: Nocturne Compendium
Blob can be found in the Great Underpass of Ginza, the Ikebukuro Tunnel, and the Labyrinth of Amala's Second Kalpa. It will sometimes drop Medicine and Life Stones when defeated in battle.
One possible fusion combination for Blob is Inugami and Datsue-Ba.
"An amorphous monster. Its body is a puddle of bubbly red liquid that grows larger and larger as it swallows people. It is weak against cold, but it's frightening regenerative powers allow it to reform itself even if frozen and shattered."
—Shin Megami Tensei IMAGINE Compendium
Blob can be contracted in Kagurazaka Zhu Que Caverns bronze level, Ueno during the in-game day, Shinjuku Babel's docks area, Suginami Tunnels' silver and grey instances, and Shibuya's Celu Tower silver instance prior to the rebalancing. It appears as a boss within DB Watanabe and DB Saitou's hacked chip instances. It appears in Shinagawa during the weekends as part of the invasion forces.
Blob first appears in Manipura, when Serph and company go to meet with the Maribel. It is slightly unique in that unlike most demons, it will not start with a full MP pool. It will instead try to put the party to sleep with Dormina and leech their MP using MP Thief. It will finally pop off a Teradyne spell once it has stolen enough MP. Multiple unsuccessful attempts at putting the party to sleep will cause it to waste turns due to insufficient MP.