A long time ago, back about 1980, I rolled up a new character and got an obvious magic-user. His initial spells included Magic Missile and he was fun to play.
But he blew the roll to learn Burning Hands. Now, for us Old School AD&D 1e types if you blow the chance to learn a spell you can never learn that spell, ever, unless some very specific or unusual things happen.
At least I still had Magic Missile!
Then I blew Shocking Grasp. And then Charm Person.And Sleep, for goodness' sake!
Now, Jonas had a 17 intelligence, so this was flat-out cursed dice!
Second level wasn't so bad, Sure, I blew Detect Evil, Audible Glamour, and Mirror Image but I had Web and Stinking Cloud.
Then 3rd level spells came. Oh, did they ever.
Jonas promptly blew the rolls for Fireball, Lightning Bolt, and Flame Arrow (I took Monster Summoning I as my 'free' spell).
So there I was, 5th level and my go-to damage spell was still Magic Missile.
So I invested the coin, took the trips into lost libraries and sages' towers, and - invented a bunch of variants of Magic Missile! By the time Jonas was 9th level he was called the Gatling Mage!
The first variant was a second level spell called:
Level: Magic user 2
Range: 10 ft/ caster level
Area of Effect: One Creature or Object
Casting Time: 1 segment
Saving Throw: None
The magic user points at a target within range and releases a bolt of eldritch force that strikes unerringly causing 2 points of damage per level of the caster. The bolt hits with enough force to throw small objects away from the caster a distance of 1 foot per level (for a 1 lbs. object); larger and smaller objects have this distance adjusted based on weight. Non-magical objects struck must also make a saving throw vs. normal blow or be broken. If the object is held by a creature that creature must make a saving throw vs. paralysis or drop the item.
Jonas' Jab is stopped by Shield and other items and spells that affect Magic Missile, such as Brooches of Shielding
As you can see, this is a very minor change - it can hit things rather than just 'creatures' and it has a few mild aspects of the Push spell added. The set damage was nice, too.