Yile's Summoning is a stat boost that allows the Subtalleon to make summons without an unhatched egg, though it adds a a 33% chance of failing. If the summoning fails, it also consumes all items attached to the submission, as well as a monthly summoning use.
Tier I
Allows the to Subtalleon summon a new Subtalleon with another Subtalleon with Yile's Summoning.
Tier II
Allows the Subtalleon to summon a new Subtalleon with another Subtalleon.
Tier III
Allows the Subtalleon to summon a new Subtalleon without any help.