Titus periodically encounters obelisks with goodies stuffed inside. Sometimes it's a new gun, others a Purity Seal ribbon to unlock new abilities. The rarest of these jewels, though, is the jump-pack, a burst-effect jet pack with excellent propulsion either up or down. Launching into the air and coming down quickly is a great way to get around bigger battlefields, but the allure is the violence it causes when attacking on descent. Boosting to a group of grounded greenskins entails a thick, syrupy mist of dark red erupting around our hero. It's an incredible moment every time  you slam down, and it's something not really seen anywhere else. It's a pity about the limited usage we get out of it -- it "runs out of fuel" after you cross a checkpoint threshold. This is also part of what makes it so enticing. Who knows when you'll find the jumpy toy again?