Aeolistophylyl's Delayed Launch Magic Missile

You create four glowing darts of magical force, which slowly oscillate around your head. When you cast this spell, and as a bonus action on any turn thereafter, while the spell still lasts, you may fire any number of the missiles that are currently orbiting your head. When you fire a dart, the dart hits a creature or object of your choice that you can see within range. A dart deals 1d4 + 1 force damage to its target. The darts may safely orbit your head for a number of rounds equal to your Intelligence modifier. At the end of each round after that, you may try to keep the darts orbiting your head. If you do not want to keep the missiles orbiting your head, you must fire them all, no action required. If you want to try to keep the darts orbiting for longer, make a DC 15 Intelligence saving throw, with the DC increasing by 1 for each additional round you try to keep the darts above your head (so the DC would be 16 the first round, 17 the second round, and so on). On a successful save, you suffer no ill effect and the darts stay where they are. On a failed save, 1d4 of the darts explode, each dealing 1d4 force damage to you. A dart that explodes then vanishes. The remaining darts (if any) continue to orbit your head. If you lose concentration on the spell, make a DC 12 Intelligence saving throw. On a successful save, you must fire all the darts still orbiting you or have them explode, each dealing 1d4 force damage to you in the latter option. You may choose to have some explode and some fire. If you fail the save, all the remaining darts explode, each dealing 1d4 force damage to you. The spell ends when there are no more darts orbiting your head, whether the last on was fired or exploded.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the spell creates one more dart for each slot level above 3rd.