An artificial Spark, it unites with an A.I. and allows them to survive in a Spark based body. They are created by Engen infused with Life Code for a body and made to grow before merging with an A.I. consciousness. In time it can develop into an actual Spark.
As part of their desire to better understand other Mechanoids and help free them from their shackles, the Plasma Heart was developed to allow other robots and mechanoids to be transferred into transformer bodies, which require some sort of spark.
They are also used to help A.I. based robots overcome Rampancy.