Final answer:
The movie franchise that features Mrs. Voorhees as the killer in the original and Jason Voorhees in the sequel is 'Friday the 13th'. Mrs. Voorhees seeks revenge in the first film, and her son, Jason, becomes the infamous killer in subsequent movies.
Step-by-step explanation:
The movie franchise in which Mrs. Voorhees is mentioned and the iconic character that appears in the sequel is Friday the 13th, Jason Voorhees. In the original Friday the 13th film, which premiered in 1980, the killer is indeed Mrs. Pamela Voorhees, who was seeking vengeance for the death of her son, Jason.
However, it was not until the sequel, Friday the 13th Part 2, that her son Jason became the central antagonist, and from there on he became the iconic face associated with the franchise. Jason Voorhees is recognized for his hockey mask and machete, and over the years, the Friday the 13th series has become a classic within the horror genre.