Galadhrim Bow

Flash
When this Equipment enters, attach it to target creature you control. Untap that creature.
Equipped creature gets +1/+2 and has reach.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

The Lord of the Rings: Tales of Middle-earth

Flash
When Galadhrim Bow enters the battlefield, attach it to target creature you control. Untap that creature.
Equipped creature gets +1/+2 and has reach.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Attaching an Equipment with its enters-the-battlefield triggered ability isn't the same as using its equip ability. You don't pay mana for the attachment, and the timing restrictions for equip abilities don't apply.

Galadhrim Bow doesn't enter the battlefield attached to a creature. Instead, the Equipment enters the battlefield and then a triggered ability attaches it to a creature. You may cast Galadhrim Bow even if you don't control any creatures.

If the target creature becomes an illegal target, the Equipment remains on the battlefield unattached, and no creatures are untapped.