Bestiary entry from the Clan Primer:
Bestiary Observations
“Rarely, during the little-understood process of Subdivision by which Flan multiply, a Flan of purest White is born, this being the White Mousse.
Known for its Tendency to swallow prey Whole, its Digestion requiring no masticatory assistance.
Posted as a Mark by a certain Moogling Moogle who lost an Article of some Value.”
Drops
| Always |  Broken Key |
Stolen
| Common - (55%) |  Potion |
| Uncommon - (10%) |  Echo Herbs |
| Rare - (3%) | Hi-Potion |
Poached
| (Nothing) |
Location
* White Mousse is the Mark for Hunt 06. Check out the Hunt 06: Lost in the Pudding Hunt page for more information.