Per 
Special Containment Procedures : SCP-5120 is to be contained in a standard humanoid cell. SCP-5120 is to be feed 5 times per day, each 2 hours apart. No other SCPs are allowed 5 km from SCP-5120 outside of testing.
Description : SCP-5120 appears to be an adult Caucasian male. Around 6 ' 1. SCP-5120 ages two times slower than a non-anomalous human. Though it needs to feed twice as much as an average human needs. SCP-5120 primary anomaly is that it reacts differently to other anomalous object's effects completely nullify them. SCP-5120 also has the ability to come back to life after 50 - 90 seconds after being neutralized, the only way to completely neutralize SCP-5120 is by old age.
By the way, here's all of the reactions had on the SCPs. I might add more.
SCP-049 when SCP-049 attempted to terminate SCP-5120 by touch, no effects showed, but SCP-5120 could still be animated.
SCP-035 SCP-035 possessing SCP-5120, did not fully take control over SCP-5120. Making the 2 entities fight over SCP-5120's physical body.
SCP-106 SCP-106 could not take SCP-5120 to its pocket dimension, but could degrade SCP-5120 into ashes.
SCP-426 SCP-5120 could not refer me in the first person, but did not get effected by my secondary ability.
SCP-173 No effects seemed to come out of SCP-173, even when SCP-5120 looked away from SCP-173, regular activicty from SCP-173 resumed after SCP-5120 was escorted out of SCP-173's containment room.
