Gives your mature entity a permanent name at a cost of 500 rift sparks. I don’t know of any power bonus from this, but at the very least it cuts down on the constant stream of silly questions in parties. You know the ones.

UristMcTarm [party]: How do I target your entity?
GlassTank [party]: target entity
UristMcTarm [party]: Oh.

The in game help reads:

No saving throw.
Casting time: 20 rounds.
Type of spell: neutral spell.
Affecting stats: int/wis.
Cast type: rift.
Spell point cost: 28.
Your entity will gradually grow in power and size as it experiences more of
this world. When your entity reaches medium size, you can bind it to yourself
giving it a permanent name.
Syntax: cast bind rift entity at <name>
This spell uses 500 rift sparks.