Gaining an Accursed Companion
System: Pathfinder | SRD | Type: animal_companion
Any character with the animal companion or mount class ability can choose to gain an accursed animal companion once a previous animal companion has suffered a violent, humiliating, or particularly horrible death. The character must then choose to gain an accursed companion while performing the ritual to replace the slain companion. At the GM’s discretion, the player might automatically gain an accursed companion unless she takes the time to seek atonement for allowing her previous companion to die.
Source: d20pfsrd