Creeping Crystal

A clove of cyan crystals begins to creep up the side of the target, latching onto them, and draining their energy. The target takes 1d4 psychic damage and 1d4 force damage once the crystals attach, and 1d4 force damage for 3 rounds afterward, at the start of their turn. You cannot target a foe with this spell until after it has expired At 6th level, the 1d4 psychic damage becomes 1d6. At 14th level, it becomes 1d8.

This spell is meant to be an alternative to Eldritch Blast and will be on a specialized spell list for a subclass I'm making for Warlock. I have very little experience with homebrew, so if there's something you'd change, tell me.