Crown of Death

You touch an undead creature, and a crown of dark energy forms around their head. While the creature is under the effects of this spell, they gain the following benefits:

• Advantage on all attack rolls and saving throws
• 3d10 + 3 bonus health
• 10 extra movement speed

When this spell ends, you may restore it as a bonus action at the cost of another 4th level spell slot.

At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, the creature gains an additional 1d10 of bonus health.