Decoy

The caster takes out a small doll that has been dressed and painted to resemble them and breathes upon it, as if giving the kiss of life.

The caster becomes invisible and an illusion of them (a decoy) appears a few feet to one side or behind. This illusion cannot interact with objects (as they pass through it) but does project the caster's voice and any other sounds they might make.

The decoy illusion has the same AC as the caster and moves as the caster does but the first attack that hits it automatically dispels it, revealing where the caster is.

If someone is paying close attention to the caster, they might detect something is not quite right (shadow in wrong position etc) by succeeding on a WIS check vs the caster's spell DC. They only get one attempt at this though and only if the caster has been observed by them for at least 1 minute.

Anyone who sees the caster cast this spell, or who detects it is an illusion by succeeding on their WIS check, can make an attack on the real caster at disadvantage, assuming they are within 5' of the caster's real body.

Detect Illusion or Invisibility reveals the caster's true position.