Vecna's Bestow Curse

You see a creature, that creature must succeed on a Wisdom saving throw or become cursed for the duration of the curse. When you cast this curse a small amount of blood with be taken from within you dealing 1 damage, you must also be willing to kill the creature.  When you cast this curse, speak the nature of the curse such as. 

• Curse of Vulnerability, reduce the target AC by 3
• Curse of Fatigue, reduce the target movement speed by half.
• Curse of Hindsight, target cannot take its reactions
• Curse of Necrosis, target takes an extra 1d4 necrotic damage from all sources
• Curse of Narcolepsy, choose 5 numbers between 1-12, at the start of each hour, the target rolls a d12. If the roll matches any of the chosen numbers, the target falls unconscious for 1d6 hours. After the initial unconscious period ends, the target must roll a d12 every hour. If the roll matches any of the chosen numbers, the target falls unconscious again for another 1d6 hours.
• Curse of the Undead, the target will slowly start to appear as if turning into a zombie, in 1d10 hours, it will appear as though the target's flesh has rotted and hair fallen out, however this is only an illusion, and the target will return to normal immediately after the curse's duration.
• Curse of loathing, the target will become obsessed with an object or creature of your choice so long as the target can see or knows of the object or creature.
• Curse of Allergies, the target becomes allergic however not deathly allergic to a creature or material of your choice.

 At the DM's option, you may choose an alternative curse effect, and can exceed the curses above if a higher spell slot is used to the DM's discretion. The DM has final say on such a curse's effect.

At Higher Levels, if you cast this spell using a spell slot of 5th level or higher, the duration is, up to 10 minutes. If you use a spell slot of 6th level or higher, the duration is 24 hours. If you use a spell slot of 7th level or higher, the duration is 1 month. If you use an 8th level spell slot, the duration is 1 year, if the spell slot is 9th the spell last until dispelled.