Grubberfly's Elegy

Usefulness
For the amount of work recquired to obtain this charm, it can be a little lackluster. While a quick mid-ranged attack can be convenient, it only deals half Nail damage and the ability will be lost unless at full HP. Not only that, but the beams don't generate SOUL upon hitting an enemy, which makes healing even harder.

That being said, it synergizes very well with Quick Slash for firing beams more quickly, Fragile Strength for increasing their power, as well as Lifeblood Heart and Lifeblood Core, to allow the player to take a few hits of damage before losing the effects of the Charm.

This charm is useful for completing the Delicate Flower quest as it allows for fighting from a distance and detonating the explosive bubbles found in Fog Canyon.

With all these things considered, it's best to use this charm when exploring areas and switch it out for a more useful charm when fighting Bosses. However, during the fight with The Radiance, the beams can deal damage to the boss without the need to jump, which can be a viable source of damage during the final battle when combined with Quick Slash. This also applies to the Flukemarm fight as the combo will make quick work of it without the need to jump in order to reach it.

The range of the projectiles is not affected by either Longnail nor Mark of Pride.

How to Acquire
Gifted by Grubfather after freeing all 46 Grubs.

Trivia
Элегия куколки
 * After all of the Grubs are freed and this charm is obtained, resting at a bench and visiting the room again will reveal that the Grubfather has eaten all of his children. The name of the charm, Grubberfly's Elegy, could be foreshadowing this, since an "elegy" is typically a poem mourning the dead, however, many fans theorize that the Grubfather is actually protecting his children by serving as a cocoon for them to metamorphose. This is possibly supported by the description of the charm and the name of the achievement for rescuing the Grubs, "Metamorphosis". In that optic, the "Elegy" could be for the Grubfather, since upon completing their transformation his children will presumably burst out of him, killing him, similar to the Gruz Mother.
 * The effect of this charm could be inspired by, or in reference to, the original Legend of Zelda. In this game, the player fires beams from their sword when their health is full.
 * It is possible for the projectile to do increased damage than using the nail regularly by equipping both Fury of the Fallen and Fragile Strength charms though the user must always have 1 mask left

Larve-mouche élégie Elegía de la Larvamosca