A laser core is a vital component of Transformer anatomy. If a Transformer's laser core is extinguished, the Transformer will cease functioning.
Generation One cartoon continuity
Laser core and Spark
It's been heavily debated what role the laser core and the spark play within a Transformer. Some fans have speculated that the laser core may be some sort of housing unit for the spark. Others have speculated that it may be a separate entity. Mechatron's on-package bio says he possesses an upgraded spark capture device which can rip the laser core out of any Transformer, seemingly confirming that the laser core is a housing unit. Additionally, Primal Prime's bio makes reference to the character's laser core housing his personality.