Autocorrect

You attempt to confuse a creature in the process of casting a spell by lacing your words with magic. If the creature is casting a spell of 3rd level or lower, each non-proper noun in the spell's name changes to a different word that is one or two letters off from the original word, a truncation of the word, and/or elongation of the word. This should be the first idea off the top of the Dungeon Master's head. The spell's effect changes to relate to its new name, potentially targeting new targets, having a different area of effect, and/or having a different duration. The power/effect of the spell should be appropriate for a spell of the same level. If the creature is casting a spell of 4th level or higher, make an ability check using your spellcasting ability. The DC equals 10 + the spell's level. On a success, the creature's spell is subjected to this spell. If the creature is concentrating on a spell or casting a concentration spell when you cast Autocorrect you have advantage on this check.
(For example, if you cast Autocorrect in response to Lightning Bolt being cast it could become Light Bulb, giving the caster a Bardic Inspiration dice for the next 10 minutes)

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the spell is confused if its level is less than or equal to the level of the spell slot you used.