It reads "Confundo" and a (?) can be seen under a confused character's name.
When used, enemies are unable to move around as they wish. When a player is confused, the direction they walk in does not correspond to the key they are pressing. Trying to use a sleep command such as "afk" or "sleep" while confused will result in the message "You are too confused to sleep." being displayed instead of going to sleep.
A Magic Skill level of 11 is required to use it.