Mr Orange

Peace Stone: referred to as SCP-XXXX

gives the holder (hereby referred to as SCP-XXXX-1) the ability to reflect harm from an attacker back onto said attacker, and any harm SCP-XXXX-1 tries to perpetrate is reflected back onto SCP-XXXX-1 as well.

Scenario 1: SCP-XXXX-1 punches another person or vice-versa, harm is reflected onto whomever is the aggressor

Scenario 2: an individual places a timed explosive, SCP-XXXX-1 walks into the vicinity of the explosive when it detonates, whoever placed the explosive receives the damage from the blast that SCP-XXXX-1 would have received, regardless of where they are.

Scenario 3: a person places a timed explosive at a position, then receives SCP-XXXX. A 2nd subject walks into the vicinity of the explosive when it detonates, the 2nd subject receives the damage from the explosive blast rather than the new SCP-XXXX-1.
(it seems that any harm planned before an individual receives SCP-XXXX and indirectly executed while the individual has SCP-XXXX does not trigger the effect.)

Scenario 4: an individual places a remote explosive at a location and afterwards receives SCP-XXXX. SCP-XXXX-1 then detonates the explosive in the vicinity of a 2nd subject, SCP-XXXX-1 receives all of the harm the 2nd subject should have received.