Harrow Hall Boarding School is a miserable place because every pupil is intimidated by Penny Benson, a girl who bullies and frightens them with claims of supernatural powers. Sandra Main is the only one who stands up to Penny and begins to suspect she is just a clever fraud.
- Artist: Carlos Freixas
- Not to be confused with the Nikki story of the same name Poison Penny 
Poison Penny – Spellbound: #16 (08 January 1977) – #26 (19 March 1977)
Reprint – Mandy: #900 (14 April 1984) – #910 (23 June 1984)