The discipline practiced by the vampires of Clan Tzimisce in the World of Darkness role-playing games by White Wolf Games Studio. Vicissitude allows the skilled practicioner to shape and mold the flesh and bone of one's self or others, and at higher levels stranger and more complete metamorphosis is possible -- one notable power is the ability to turn into a sentient, mobile slick of blood, immune to all forms of damage but fire and sunlight, and able to seep through the smallest cracks. It does, however, confer the unusual disadvantage of being able to be drunk. What's so bad about being drunk? Just you ask a glass of water! (apologies to Douglas Adams)

The Tzimisce see the use of Vicissitude as both a science as an art form, performing terrible experiments in their laboratories and turning themselves into beings of terrible beauty. White Wolf has published supplements which suggest that vicissitude isn't a true vampiric discipline, but rather an alien disease that the True Black Hand brought back from the Deep Umbra; however, in 3rd Edition, this idea seems to have been edited out of the continuity. As always, White Wolf leaves the use or ignorance of such ideas to the individual storyteller, in accordance with the Golden Rule of White Wolf.

The servitors and war ghouls known as szlachta and vohzd are created with Vicissitude, and the discipline formed the basis of the path of enlightenment known as the Path of Metamorphosis, which many Tzimisce follow.