Sandra Dier is a character in Friday the 13th Part II, played by Marta Kober.
In the summer of 1984, Sandra goes to Camp Crystal Lake with her boyfriend Jeff Dunsberry and friend Ted Bowen who pranks them by getting their car towed.
Later on, as Jeff plays video games with Mark Jarvis, she tempts him into having sex. After having sex with Jeff, Sandra notices Jason Voorhees enter the room, wielding Ted's spear. Before she can warn Jeff, who is on top of her, Sandra is killed when Jason drives the spear through Jeff, her body, the bed and into the floor. After killing her, Jason hides Sandra's corpse in the bed he murdered her and Jeff in.