Marshlights have no physical form, but can appear as glowing lights of indistinct appearance or as luminous humanoid or animal figures.
Marshlights cause no damage in combat and are themselves impossible to harm - although they may be banished by a single hit from a magical weapon. Characters seeing a Marshlight must make a WP test or be mesmerised, following the Marshlight wherever it leads, generally into sinkholes and quicksands. Mesmerised victims may be restrained by any characters who still retain their wills and, if restrained or struck, the victims are allowed another WP test to throw off the mesmerism. The compulsion automatically ends if the Marshlight goes out of its victim's sight.