Johnny Grimes was the killer in the movie "Room 13" He was played by Taylor Goligoski.
There is a horror movie from 1977 about a killer alligator called 'Eaten Alive' And there is a 2007 Australian movie about a killer crocodile called 'Black Water'.
The movie is called 'The Leprechaun'.
The 1988 release of the movie 'Pulse'.
Scream
Very doubtful.
I believe the movie you are thinking of is Scream.
The actor playing the killer in the Geico horror movie commercial is Jonathon Kite. He is known for his work in various television shows and films, and in this ad, he portrays a humorous take on the horror genre, adding a comedic twist to the classic trope of the killer.
There are lots of movies, but one of them is Disturbia.
Sleepaway camp
In the attic
Blood, dead people, weapons, and a killer.
Silent Night, Deadly Night