Arcane Wednesday - From Pathfinder Blur https://www.d20pfsrd.com/magic/all-spells/b/blur
This is a spell that has been around for many editions of D&D as well as in the Pathfinder game. It is almost always a 2nd level spell, and it has similar practical effects, but the mechanics change from edition to edition. In Pathfinder the spell makes the target harder to hit by imposing a percentile roll after every attack. There is a 20% chance the attack misses, even if the roll was high enough to hit.
In D&D 5e, however, this becomes simple disadvantage on the attack roll. In this version the attacker rolls his d20 attack twice and has to take the lower result as the actual attack.