Jenny and Mandy are the Haus ghosts, whom according to Ransom most definitely do not exist[1].
Originally Jenny and Mandy were sisters in the Theta Alpha Theta Sorority, which owned the Haus for sometime up until 1993[2]. Presumably they both passed away in a tragic accident during a rush event, which caused the Haus to be abandoned and it stood empty for a decade until it was purchased by the Samwell Men's Hockey Team in 2003[2].
Jenny and Mandy are particularly fond of Ransom, and have a habit of tormenting him in various ways. Some of their typical antics include:
- Displacing Ransom's things, such as his jock strap the day before a game[3]
- Giggling in Ransom's presence[1]
- Disturbing Ransom in the bathroom[1]
- Touching Ransom's butt[1]
- Playing 90s hits, such as 'Oops!... I Did It Again' by Britney Spears[1] and/or the Samwell Fight Song[2]
- Creating cold spots that only Ransom seems to detect[1]