One thing is bound to confuse you a great deal when you first start Ratchet & Clank: Rift Apart, and that thing is the optional Zurpstone side quest on Sargasso. After finishing up your time at Scarstu Debris Field (Zurkie’s), Mort will call asking Rivet to come back to Sargasso to help out with a situation regarding Trudie–an alien pterodactyl-looking creature. If you choose to return, you’re treated to a new side quest where you must collect Zurpstones first to feed Trudie and then more after that to earn valuable collectibles. The task itself is simple, but the further you go along with the quest, the more confused you’ll likely become, as you start to notice Zurpstones in places you can’t even reach.
Focus on collecting the first 15 Zurpstones and return to Mort to receive your first reward: a pair of Galactic Ranger boots. He’ll then tell you to collect 30 Zurpstones for a Galactic Ranger helmet, and then all 60 Zurpstones for a Spybot–but now, you’ll have Trudie to help fly you across Sargasso to reach those seemingly out-of-reach Zurpstones. The job will seem easy from here, at least, until you realize Trudie can’t collect the Zurstones that aren’t near perches for her to mount on, particularly ones that are on mountains and Gelatonium factory towers.
You can’t get these Zurpstones because Trudie has a hidden attack that you first need to unlock. Apparently, Trudie needs to work her way up to breathing fire again, which will only happen once you collect 45 Zurpstones.