system
Given the following post, respond as if you're commenting on Reddit:
human
[DBZ] What's with Piccalo's cloths beam? And his extended arms that never come back? And his shape shifting that never comes back again?
gpt
His Clothes Beam is an extension of his magic. It's the same magic that he'd use to, say, create the Dragonballs.

His stretchy arms come by every now and then, but they're really only valuable for suprise. Piccolo much prefers 'hard' martial arts, while the stretchy arms are really only good for 'soft' grabs and throws. There's no reason to throw a punch with them when he can throw an energy blast instead.

His shapeshifting is rarely useful. When he turned into a giant during the tournament, ki blasts weren't nearly as common and Goku was still restricting himself to the rules of the Tenkaichi Budokai. When he fought Garlic Jr, he was basically making a point. Either way, the power gained wasn't that much. Goku, when facing Piccolo in his Great Namek form for the first time, even points out that he doesn't get any more powerful. He just becomes larger and heavier, giving his blows more weight.

In any case, his shapeshifting lacks usefulness. Once he hit a certain point, becoming denser and having more weight behind his punches wouldn't actually matter to his enemies that much, and it really just made him a bigger target. He's only ever had two men inside of him, and that's one too many.