The Nova Power Core is a device of Human design that provided a great level of energy.
Generation One cartoon continuity
Megatron sent the Insecticons to devour the Nova power core in order to be strong enough to siege a compound at Iron Mountain. The energy from the core made the Insecticons far stronger than normal and made them grow in size. They, however, did not know that the Nova power core was incompatible to the Insecticons' Trilithium stomachs.