Arcane Bombardment

You dive into your own timeline, duplicating the time used to cast spells for future use.

Once per turn while concentrating on this spell, when you use a spell slot to cast a spell using an Action or a Bonus Action, immediately cast all previous spells recorded with this spell during this casting. These spells are cast at the level recorded for each individual spell. You must immediately spend the spell slots required to cast each spell, ignoring any restrictions regarding spell slot usage per turn. You may choose the targets for each spell. You must cast the spells in the order that they were recorded. Afterward, record the spell that was used to trigger this effect. 

If you are unable to cast a recorded spells due to missing the required spell slots or not having a valid target for the spell, this spell immediately ends. Any spells left in the list that have not been cast are lost. 

When this spell ends, the caster is Incapacitated and has a Speed of 0 until the end of its next turn, as a wave of lethargy washes over them.