Stacklady's causes the target to turn temporarily into a frog, at that a Frog that looks an awful lot like what they were before the spell was cast. The duration of the spell is fairly limited, but does increase with higher skills.

 

Being a frog has the following effects:
Stat penalties of -2 constitution, -1 strength, and -1 dexterity
Frogs cannot hold things.
Frogs cannot cast spells.
Frogs have a dodging bonus of 350.
Frogs can't say anything other than "Ribbit".

A failure causes the caster to be turned into a frog instead.