This article's content is accurate to the most recent public game version, 0.4.8d.
"[5 Turns] Conjures a protective slime dress. Reduces all Physical damage by 50%. Adds 25% NUL."
Cost: 10 MP
Source: Eric(a) - Siphoning the Slime Queen's Core.
Slime Gown is a spell that applies a buff for five turns to the user that reduces 
Sharp and 
Blunt damage taken by 50% and gives +25% NUL. The spell cannot be cast again while it is still active.
This can be considered a variant of Slime Body from the Slime Princess' Core. While this spell doesn't give 
Acid immunity, it's physical resistance is higher, provides one of the few ways of raising magic nullification, and does not include the 
Fire weakness.