Melf's Acid Arrow

Level & School
2nd-level evocation
Casting Time
Action
Range
90 feet
Components
V, S, M (powdered rhubarb leaf)
Duration
Instantaneous
Classes
Wizard

A shimmering green arrow streaks toward a target within range and bursts in a spray of acid. Make a ranged spell attack against the target. On a hit, the target takes 4d4 Acid damage and 2d4 Acid damage at the end of its next turn. On a miss, the arrow splashes the target with acid for half as much of the initial damage only.

Using a Higher-Level Spell Slot. The damage (both initial and later) increases by 1d4 for each spell slot level above 2.

Level & School
2nd-level evocation
Casting Time
Action
Range
90 feet
Components
V, S, M (powdered rhubarb leaf and an adder's stomach)
Duration
Instantaneous
Classes
Wizard

A shimmering green arrow streaks toward a target within range and bursts in a spray of acid. Make a ranged spell attack against the target. On a hit, the target takes 4d4 acid damage immediately and 2d4 acid damage at the end of its next turn. On a miss, the arrow splashes the target with acid for half as much of the initial damage and no damage at the end of its next turn.

Using a Higher-Level Spell Slot. When you cast this spell using a spell slot of 3rd level or higher, the damage (both initial and later) increases by 1d4 for each slot level above 2nd.

Melf's Acid Arrow 5.5e 2024 vs. 5e 2014 edition differences

Both versions are essentially the same mechanically. The 2024 version clarifies that on a miss, the splash damage is only half of the initial damage, with no additional damage at the end of the next turn. Damage increases by 1d4 per slot level above 2nd in both.