Befriend [Custom Spell]

[Yunru]

Befriend
5th level enchantment and evocation spell
Casting time: 2 actions
Range: 300 feet
Components: VMS
Duration: Instantaneous

A beam of pink light shoots towards a point you choose within range and then blossoms into a sphere of magical energy. Each creature in a 20 foot radius sphere centered on that point must make a dexterity saving throw. A target takes 12d6 psychic damage on a failed save, or half as much damage on a successful one. If this spell reduces a creature to 0 hit points, the creature falls unconscious and is stable and charmed.
At higher levels. When you cast this spell using a spell slot of 6th level or higher, the damage increases by 2d6 for each slot level above 5th.

[LibraryOgre]

How long does the Charm effect last?

[Yunru]

Forever.
Such is the power of friendship.

[JNAProductions]

Psychic with a Dex save?

Also, that's just really highly damaging.

[Yunru]

Psychic with a Dex save?

Also, that's just really highly damaging.

I'd say it's on par with the DMG's suggestions for a 5th level slot.
And yes, you resist the mind warping effects with your HP. You avoid the mind warping explosion with your Dex.