Percursor Orbs are collectable items, and are worth more of the currency than eco is. They are floating egg shaped things that are gold. The translations are, the top half is "NaughtyDog," and the bottom half translates "Precursor." They are usually glowing but not all the time. They make a "Ding," or a "Boing," or a "Booh," sound when obtained. It is unknown were Jak stashes these precursor orbs, possibly his back strap, or, if they're made of eco, he obtains them by obsorbing them (kind of like eating them). They are used to buy secrets and upgrades.