Brainiac 5, a Coluan.
Coluans are a sentient humanoid race native to the planet Colu. They have green skin. The term Coluan would also apply to the race of mechanical lifeforms created by the Coluans, known as the Computer Tyrants, who would come to rule the planet. These eventually redesigned themselves to resemble their Coluan creators.
Genetic Engineering
The Coluans have genetically engineered themselves. Among the improvements they've made to their physical structures, they increased their intelligence, making themselves into Level 8 intelligences.