A 1st level spell fits into a slot of any size, but a 9th level spell fits only a 9th level slot. Page 201, Dungeon & Dragons Players Handbook 5th edition. One class whose spell slots don't work ...

The target cannot reply, but it's still a great boon to have that doesn't cost a D&D 5e wizard any of their spell slots. This feat is excellent for wizard who like to use spells that make ranged ...