Arden's Utterly Believable Death Feign

Upon receiving damage you may use your reaction to become invisible. At the same time, an illusory double of your appears where you are. The illusory double acts as if it received a lethal blow from the damage you just received, realistically mimicking all death effects (such as fire, necrosis etc) including sensory effects such as heat.

The attacker and all bystanders must make investigation saving throws (equal to your spell save DC) to determine the illusion to be false. Otherwise they are legitimately convinced that the death is genuine. Physical inspection reveals the dead (or dying) image to be an illusion, because objects pass through it. Creatures who failed the check would generally not check, however.

The invisibility acts as the level 2 spell of the same name, except that it lasts for only 2 rounds (it ends upon attacking or casting a spell). The illusory double remains for the duration of the invisibility. At the end of the duration, the illusory double seeps into the closest surface and the invisibility ends.