Melf's acid arrow

Acid arrow, sometimes called Melf's acid arrow, was an arcane conjuration spell that propelled an arrow of acid from the caster's hand that continued to corrode what it struck.

Effects
After the Year of Wild Magic, 1372 DR, the caster launched a single arrow of acid from their hand. It had an effective range of over 440 feet (130 meters). If it struck the target, only it was harmed by the acid. For more experienced mages, the acid lingered and continued to burn for an increasing length of time until it was neutralized or the effect expired.

After the Spellplague of 1385 DR, the spell created a shimmering arrow made of a green, glowing liquid. It exploded on contact with its target, burning it and spraying sizzling acid over adjacent creatures to slightly injure them as well. Even on a miss, it was still injurious. The acid continued to burn until removed.

Components
In addition to verbal and somatic components, the spell required powdered rhubarb leaf and the stomach of an adder. It also required a dart as a focus.