Sometimes Gulliver, the seagull from Animal Crossing: New Horizons, will wash up on your island in pirate garb, rather than his usual sailor outfit.
Just like his usual sailor appearance, pirate Gulliver (or Gullivarrr) may wash up on your shore, needing help getting back to his crew. To help him out, you’ll need dive and grab a his communicator. Note that you’ll only need to find one communicator, as opposed to five communicator parts.
You’ll need a Wet Suit in order to swim in the ocean and find it. Just like when you dive for sea creatures, you’ll press Y to dive down to pick up objects bubbling in the ocean. While some of them will definitely be sea creatures, you’ll find the needed gadget eventually.
As a reward for helping him out, he’ll give you a set of fancy pirate furniture or clothing. Just like his other reward set, it’ll get mailed to you the next day after you help him.
His appearance seems to be random, as you can still get his sailor-outfitted self to appear on your island as well. If you’re itching to nab all his new goodies immediately, you can time travel until you see the bird on your shores.
It’s unknown if helping him when in his pirate suit counts towards the Golden Shovel unlock requirements.