Inklings confirmed!

I think it's just a placeholder if someone tries to run a hacked character or something, so the game has at least a voice file to run rather than just crashing.

Of course, I'm just guessing. This is still pretty interesting.

And here I was thinking that it was not major enough to post on VGChartz instead just posting on GameFAQs. I guess things come back around on the Internet.

''From another dimension'' might point to a franchise not yet represented.

I'm still very sceptical though

That is so generic it could be anyone.
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Cthulhu enters the abyss!!

Intruder?

Could just be generic for in the case that it is not able to recognise the figther - either for DLC characters like Mewtwo or in case of hacking or whatever... it could be because they knew there might be new DLC characters but I don't know if it really gives more evidence that they might be likely.

On the subject of new DLC characters, I am slightly disappointed that they specifically said that they don't intend to do more "paid DLC" in the future (though obviously I know they can go back on it)... I get that they want to look as though they aren't releasing a partly completed game or holding content back, but you only have to look at the rest of the industry to see that that isn't really a big problem for sales. Hell, people these days probably hear "Will not have paid DLC" and think "Oh, that's not as valuable a proposition as something that will have more content in future!".

I know that new characters are a huge amount of work for Super Smash Bros (not like, say, adding the new characters in Mario Kart), but I still think it would be a good idea for the future now that they are embracing it with Mario Kart. There are some great opportunities to add characters like Bayonetta, the Inklings from Splatoon, perhaps one of the characters from Hyrule Warriors (either new character or one from Zelda that has now been used as a playable character, like Midna). And it would offer chance for Amiibo interaction too - and no, I'm not suggesting making new characters that require the an amiibo, but you can easily see some scenario of buying, say, an Inkling Amiibo and getting the download code for that character (or perhaps multiple characters if they release a couple as one DLC), with the option to pay to download the character without the amiibo.

Reggie? Cthulhu? Mewtwo? Master Chief?

Probably Mewtwo

I think this is likely.  Just a placeholder for any kind of test character or anything that doesn't have dialogue.  Similar to the "I HAVE NO GREETING" message that you sometimes see in other stuff.