Recent multi-platform mega-hit Palworld, described as "Pokémon with guns" (with most of its gameplay similarities actually rooted in Ark) has already been accused of plagiarism by the fan community. The original designs are technically distinct, but it's pretty difficult to argue there was no inspiration whatsoever.
But modders on the PCs are never content to leave these tenuous connections in an unplayable form, so ToastedShoes on Twitter and YouTube chose to announce a Pokémon Palworld conversion mod — complete with footage of the mod in action. We do not have this footage, because Nintendo issued a DMCA strike on all videos of the mod within 24 hours. [h/t The Verge]
Now, technically, the Palworld Pokémon mod never saw a public release, and was planned as a free release. However, the quick action on the announcement video served as a chilling effect on the mod developer: ToastedShoes quickly announced he planned to "tread lightly" regarding the mod's release, potentially cancelling it outright.
Before that happened, though, the developer posted an over 15 minute video of the mod in action. The mod replaces both in-game Pals with Pokémon and the playable character with Ash Ketchum, a character from the anime. Aside from that, it's unaltered Palworld gameplay, which means all of the games edgier mechanics are still in play and put to use on these beloved, very copyrighted characters.
While some video game companies are either much more welcoming to fan games and fan mods or outright encourage them, Nintendo is absolutely not one of them. Especially not when the mod is placing one of its highest-valued properties in a game meant to directly rival the very same property. Even Pokémon fangames with fully original monsters and assets like Pokémon Uranium weren't safe from Nintendo's copyright hammer.
Whether or not this mod ever sees a public release, the message sent by it is fairly clear: Everyone playing Palworld knows these designs are, at the very least, highly influenced by Pokémons, and that's part of the appeal. Seeing as Nintendo has yet to take public action on the main game itself but didn't hesitate to take down announcement videos of a Pokémon mod for this game, this might mean Palworld itself is safe (or it might mean Nintendo is hard at work with its lawyers).