There's a Hawaiian shirt of Chunk doing the "Truffle Shuffle"

Two things:

1. I'm 99.9% sure this is an unlicensed Goonies product, which means child-actor-turned-entertainment-lawyer Jeff Cohen (aka Chunk) won't see a dime from its sales (maybe I'm wrong!);

2. A 2015 UPROXX article describes how the film's director Richard Donner felt about that scene and what he did to help Cohen later in life:

Watching the movie as kids, we probably werent too aware of how mean the Truffle Shuffle was, mainly because Chunk reluctantly performed it for his friends and then went about his business... However, Donner recalls it as a painful scene to film and it was ultimately the catalyst for his lasting relationship with Cohen.

There was no direction, Donner explained. I dont take any credit for that, it was just Jeff. He had to stand on that stump and be ridiculed by his friends so he could come in the house, and he did it as best as that character could do it. So much humor comes from pain. Although, Im sure he was too young to be analytical about it, but Im sure that was part of his instincts. It was a painful scene.

In fact, Cohen told us that Donner hiring him as a production assistant when he was jobless was what opened the door for him to learn the business of show business.

Jeff became very special as an individual for me when he did the Truffle Shuffle because there was an honest pain in that scene for that little boy in front of those little kids, Donner said. When I saw that, and you could see it, my heart went out. When I told Lauren about it we decided were going to have to help him go to work on his body and his mind. So, I got him a gym and some instruction and someone to work with. He lost lots of weight and built this great physique and became captain of his wrestling team in high school, captain of his football team, and president of his school class for two years in a row. Im not saying I did it, but I know that when he started putting pride into his body and self a lot of things changed. I was probably closer to him.