A construction crew working on a new Alaskan oil pipeline has uncovered the frozen Blob. Not knowing what it is, the construction foreman brings a small chunk of it home to southern California with him, upon which it promply escapes, grows, and terrorizes the community, slinking through the sewers. Eventually entering the brand new bowling alley (and attached, still-under-construction ice-skating rink), the Blob is ultimately defeated by freezing the ice rink floor. A decidedly campy film, Beware! nonetheless plays many monster movie tropes dead straight, particularly the Cassandra Truth-spewing heroes and the Obstructive Bureaucrat who runs the bowling alley.
This film provides examples of:
- Actor Allusion: Due to being directed by Larry Hagman, after Dallas became a hit, the film was reissued with the Tagline: "The Film That J.R. Shot!"
- The Alcoholic: Chester.
- Black Dude Dies First: Marianne. Well, technically it's a black woman, but Chester soon follows.
- Camp: The '70s sequel.
- Dead Star Walking: Of the five actors advertised on the film's poster, only Robert Walker has any more than a few minutes of screentime. And of the remaining four, only Godfrey Cambridge's character has any particular relevance to the story outside of being a random Blob victim, and even then only because he happens to be the poor schmuck who unwittingly retrieves a sample of the original Blob and allows it to thaw out.
- Decoy Protagonist: The film starts out focusing on Chester and his wife Marianne before the Blob eats them both.
- The End... Or Is It?: The film ends with the Blob frozen (again), but a thoughtlessly-placed TV light thaws enough of it out to allow it to attack Sheriff Jones as he gives an interview.
- Improbable Infant Survival: A junior campers troop is attacked (offscreen) by The Blob. The scout leader is killed, the kids escape.
- Large Ham: The mustard-plant obsessed Scoutmaster Adelman.
- One-Book Author: This was Larry Hagman's sole feature film as a director.
- Recursive Canon: Beware! The Blob has the Blob devouring a man while he's watching the original film on TV.
- Sealed Evil in a Can: A foreman for an oil pipeline construction crew brings home a chunk of the Blob from Alaska (where it had been deposited in the original film) in a sealed thermos.
- Too Dumb to Live: When an uniformed policeman confront the Blob, he shoots it with his service revolver but it has no effect. He then repeatedly shoots at it, but it never occurs to the officer to retreat, so the monster merely engulfs and devours the officer when he trips.
- Unwitting Instigator of Doom: Chester is the one who brings the Blob home, while Marianne is the one who inadvertently allows it to thaw.
- You Have to Believe Me!: Particularly notable in this one, in which Lisa is not believed... mainly because she just keeps mewling "It came after us!" ad infinitum.