The Krew clone is an enemy encountered only during the Krew bossfight in the "Beat Krew in weapons lab" mission in Jak II. They are green, holographic, miniature clones of Krew, although their exact composure is unknown, they are capable of electrifying themselves to damage enemies they run into (much like the spydroid).
They are relatively easy to avoid in small numbers, but as the fight continues will spawn in increasingly large groups. The Blaster's aerial wastelander combo ( + + ) is effective but the best tactic to use is to stand in the doorway between the platform and the elevator and to rely on the Scatter Gun's massive spread shot. The blast will be large enough to repel any and all clones that attempt to enter the doorway, while the fixed position ensures they will bunch up, making it easy to shoot them down en masse. Melee attacks are, due to the clone's electrification, not capable of dealing damage and instead will hurt you.