The Blob is an amorphous mass of alien goo that appears in the 1958 film of the same name. Appearing as nothing more than a mass of red gelatin, this creature possesses animalistic intelligence, acting purely on the instinct to feed. It feeds on flesh and gains mass as it consumes other creatures.
In the film, the Blob arrives on Earth after it is carried within a meteorite that impacts just outside a small town in Pennsylvania. An old man finds the meteorite and pokes it with a stick, inadvertently splitting the extraterrestrial rock open and revealing the strange blob of goop inside. The Blob attaches itself to the old man's hand, causing him great pain and distress at it slowly dissolves his arm.
The old man is later hospitalized and doctors attempt to study the Blob and remove it, but it soon grows and completely devours the old man as well as the hospital staff before it breaks out and goes on a rampage across town. Each time the Blob eats a person, it grows in size, but the disappearances of its victims all seem to be isolated incidents and so the authorities do not learn the truth of what is happening for some time.
Steve Andrews, a teenage boy who ran over the Blob's first victim, tries to warn people about what is going on, but his warnings are dismissed as childish pranks. It is not until the Blob devours several people in a movie theater that anyone listens to Steve, but by then the Blob has grown to horrendous proportions. Guns have no effect on the creature and the Blob almost engulfs a diner while Steve and his girlfriend are trapped inside.
Steve's brother Danny attempts to electrocute the Blob by dropping a damaged power line upon it, but all that accomplishes is setting the diner ablaze. Neither fire nor electricity affect the monster, but when Steve sprays the flames with a CO2 fire extinguisher, the Blob recoils from the cold rush of gas. Having discovered the creature's weakness, Steve calls out to Danny and tells him to freeze the beast. Danny gathers up his friends and they take several fire extinguishers from their school and set them on the Blob, driving it away from the diner and then freezing it.
With the Blob defeated, the Air Force is called to carry the prone creature off to the Arctic where the low temperatures will keep it frozen indefinitely.
The Blob does little else except eat and grow. It preys on humans and dissolves their flesh on contact, gaining additional mass with each victim consumed. It moves slowly but can envelop any objects smaller than itself and is unharmed by heat or electricity.
The Blob is vulnerable to the cold and can be frozen solid by low temperatures, rendering it harmless.