Arcane Bomb

You put the apology letter in the bag of holding, then spend a 1 hour ritual channeling all of your arcane energy into the bag of holding. The ritual consume ALL of your spell slots, other creatures who have spell slots can join you in the ritual (even if they can't cast this spell) and spend ALL of their spell slots as well. For every level worth of spell slots consumed by the ritual (except the one used to cast it) it will do 1d10 radiant damage (Each 1st level slot consumed by the ritual will add 1d10 damage, 2nd level will add 2d10 per slot, 3rd level will add 3d10 per slot, etc).

After the ritual is complete the bag is sealed and a small lock appears on it, the bag has been turned into a magical bomb. To use the bomb place it in the desired area, break the lock and run. Once the lock is broken the bomb will detonate after a certain amount of time, determined and the end of the ritual. When the bomb detonates all creatures within 1000 feet take radiant damage (amount is determined by the ritual), each creature within 3000 feet takes half damage. Any creature within 10 miles of the bomb when it detonated is blinded and [Tooltip Not Found] for 10 minutes.

For the next 5 years any creature that is within 1 miles of where the bomb detonated takes 10d6 necrotic damage at the start of their turn and has their maximum hit points reduced by that amount. For the following 10 years any creature that is within 1 mile of where the bomb detonated takes 5d6 necrotic damage at the start of their turn and has their maximum hit points reduced by that amount. All plants within 1 miles of the bomb wither and die upon detonation, and no new plant life can grow there for the next 20 years, even by magical means.