I also second any Sci Fi channel original, or the MST3000 picks. Laserblast was a particularly bad MST one.
Troll 2 is so famously bad that it has a huge cult following. They even made a documentary about it. The movie is hilarious though, so it can’t be the worst.
My personal pick is Jaws 4. The descendant of one of the previous movie’s sharks begins terrorizing the Brody family specifically. In the beginning, it leaps out of the water and bites off a Brody’s arm, then he falls in the water and is eaten. So the mom decides she needs to travel far away. She doesn’t go to Kansas, she goes to Bermuda. Well, the shark follows her a few thousand miles from New England to Bermuda and starts hassling her and her other son there. Eventually she gets on a sail boat to go fight the shark in the finale. No weapons, just a sailboat. Somehow the shark impales itself on the boat and all is well.
Why they didn’t just stay out of the water and just remained on the beach is beyond me.