That Metroid Dread rumour? The one where Nintendo were meant to be working on a new Metroid handheld title? And which was supposedly alluded to in Metroid Prime 3? Yeah, no. No dice. Seems there was a cock-up in the game's creative process, and something that was dreadful but not in any way related to any possible Metroid handheld games made it into MP3. Game director Mark Pacini:
We actually had a fictional element of something else in the game that by a large coincidence could be read that we were giving a hint about "Metroid Dread" which was not the case. It's a complete and utter coincidence.
Glad that's sorted. Kind of. See, they go on to make a complete mess of that explanation, stumbling over all kinds of comments like "That's all I can say on it", which will no doubt serve as further fuel for the faithful's great fire of handheld hope. Retro Studios Answers The Dreaded "Metroid Dread" Question — And Other "Prime" Exclusives [MTV]