Noodlers are interesting little Bugsnax in that they can never seem to get enough heat. You can find the Noodlers swimming in lava in a cave beside Floofty. This is quite the problem, as you cannot go into lava without being set on fire.
Thankfully, you can lure the Noodler out of the lava using hot sauce from your Sauce Slinger. There are two hot sauce plants in the save, so stock up well before you start this process. You need to lure the Noodler to one of the Paletoss Grande that are walking around.
You can find one in the cave system itself, up to the right, and another walking around on the beach. You definitely want to bring the Noodler to the Paletoss Grande, not the other way around. The Paletoss will charge the Noodler, putting out the fire thanks to the ice that covers its body.
If you are too close to the lava, it stands a good chance of knocking the Noodler back in, so you won’t be able to catch it. The best way is probably to lure the Noodler to the beach, let the Paletoss Grande smash into it, then run up to it and hit Square to catch it in a net.
It can be a good idea to lurge the Paletoss Grande into the lava, letting it split into two Paletoss, as it gives you two different Bugsnax that you can try and use to put out the fire on the Noodler.