Found in Irithyll of the Boreal Valley.
From the Church of Yorshka, make way until reaching the open area with the lake surrounding the city. Proceed into the waters and look for a semi-secluded area on the far right. The spell can be found on the dead body of a Man-grub.
Restores HP for the caster and nearby allies equal to 5.5 times the Spell Buff of the catalyst. This multiplier is reduced when using a catalyst that also scales with Intelligence, such as Crystal Chime and Sunless Talisman.