There's always a bigger fish. The porgs won't leave Chewbacca the Wookiee alone, but they might be the only ones who can save him when he's captured by a sea creature.
In the opening credits, BB-8 and a Star Wars ball lead the way followed by Rey, Maz Kanata, Finn, Captain Phasma, two stormtroopers, Ben Solo, Han Solo, Chewbacca, and three porgs.
On an Ahch-To island, while the Wookiee Chewbacca is peacefully resting, pesky porgs wake him up trying to feed him some kind of plant, which clearly isn't to his taste, even though he's hungry.
Woken up, Chewie decides to try fishing for food, but the porgs refuse to turn their attention away from him and sit on him, while he waits for a fish to bite. All he retrieves is an old boot though, which the porgs try to steal. This angries Chewbacca greatly and he forces the birds to retreat into the ocean, where the porgs are easily able to find small fish, mocking the Wookiee with them.
Seeing that other methods have failed him, Chewbacca prepares a trident and a rebreather and dives into the waves to find the elusive fish, finally filling his empty stomach. The porgs try to follow him underwater as well, but Chewie manages to lose them in a kelp forest.
Chewbacca plunges his trident into a fish resting on the sea floor, which immediately turns red and tries to flee, not realizing that the Wookiee will hold on to his weapon and let himself get dragged by the sea-dweller. The fish then plunges itself into rock and dies, by coincidence also waking up another sea creature, who had been sleeping in the same rock.
Chewie jumps out of the water to celebrate his first catch, and for a moment is even sad that there are no porgs to celebrate with him, but the awoken creature uses its light-bulb to hypnotize the Wookiee before taking him back underwater, now encased in some kind of purple bubble, which appears to keep Chewbacca in stasis.
Unbeknownst to Chewbacca, resting once again, the creature takes him to the den of its much larger relative, which keeps the purple bubble, filled with various sea critters, as food storage, teasing that it won't be long, before Chewie is eaten as well.