Win the Tyhrra-Guise and Return to the Phoenix are missions in Up Your Arsenal, taking place in Annihilation Nation, Station Q9. Shortly after Qwark recovered his memory, Sasha Phyronix informed Ratchet and Clank about a gadget known as the Tyhrra-Guise, which can disguise the wearer as a tyhrranoid. Ratchet obliged, having faced many deathcourses before, in the interest of obtaining the gadget. Along the way, Ratchet also obtained the second Qwark vid-comic, Arriba Amoeba!.
Upon arriving at Annihilation Nation, you will automatically enter the "Deathcourse Challenge" gauntlet following a short cutscene. Once complete, you will obtain Arriba Amoeba!, and automatically enter the arena battle, "Grand Prize Bout".
The "Deathcourse Challenge" is the first gauntlet in Annihilation Nation, providing the second Qwark vid-comic. The gauntlet begins with a set of platforms, two of which are fire traps which will periodically release flames and make them impassable, meaning the player should jump to traverse them just after the flames stop and use the platforms in the middle for safety.
After this is a room with blade bots, which are small, swarming enemies that can be destroyed quickly with either the Plasma Whip or Suck Cannon. Standing on the switch will open a path to the left. This path leads across a zigzagging set of platforms, with laser turrets that will rise when Ratchet is close and fire; the laser turrets can either be destroyed with one hit from any weapon, or deflected with the Refractor. Behind this is a laser bot that will fire a laser in front of it moving across its set path; this is a moderately armored enemy that can be destroyed from range with a weapon such as the N60 Storm, and the laser can just be jumped over to avoid it.
Left from here, two laser bots are seen firing from elevated platforms, before the path leads right. Along here is a set of platforms with flames; jump over the flames as they are about to appear for the first set, and for the second set, only cross the platforms when the flames have switched, then destroy the laser bot to open the path to a room filled with crates and blade bots.
Standing on the switch in this room will open up a path on the right, which consists of a single bridge across, a group of Blade Bots, and a spinning laser bot. Behind this is another room in which a laser bot will teleport in, and activating the switch opens a path to the left. Along this path, several push blocks will appear from the wall, and should be jumped over when possible, while the Blade Bots and spinning laser bot should be destroyed. Following this, the gauntlet is complete.
Grand Prize Bout
The "Grand Prize Bout" is the first arena challenge, in which you battle rounds of enemies. For the first round, you will fight gladiators, which are moderately armored melee enemies that fight in clusters. A good way to defeat them is to wait until they cluster together and use the Nitro Launcher, thrown Plasma Whip, or charged Shock Blaster to damage multiple at once. For the second round, bash bots and laser bots appear; these are moderately armored robots that attack in melee range and in medium-range respectively. Once again, destroying clusters using the Nitro Launcher, Plasma Whip, or Shock Blaster is effective.
The third wave consists entirely of blade bots. The Plasma Whip or Shock Blaster can make quick work of them and use ammo efficiently, or alternatively, the Suck Cannon can suck them up to use them in the next round, which consists of laser bots, bash bots, and gladiators.
After this, the strategies are mostly similar for the next few rounds, with the exception of the sixth round: in it, an inferno crate appears. As the inferno crate grants temporary invincibility and causes normal OmniWrench attacks to kill in one hit, it is quite useful to kill enemies as quickly as possible so that it may last into the next round.
Return to the Phoenix
After both challenges are completed, a cutscene commences as Ratchet obtains the Tyhrra-Guise. Though you will be asked to return to the Starship Phoenix, consider instead fighting more arena battles and participating in more gauntlets for bolts. The rewards are fairly substantial and can allow you to obtain weapons that are particularly effective in the next few missions, such as the Agents of Doom.
When you are satisfied, or are finding the challenges too difficult, return to the Starship Phoenix to continue with the story as you can return to the arena at any time. Two missions open up once returning to the Phoenix: "Infiltrate the underwater hideout", which takes place on Aquatos, and "Play the Qwark vid-comic Episode 2", in which you complete the second vid-comic, Arriba Amoeba!. You can complete the second vid-comic at any time, though it provides a reward in bolts that could be useful for any mission.