MacBook Pro constantly deleting. Won't let me login. (Vid included)

[Auzzyy]

So out of the blue my Mac decided to spaz out and is now constantly backing out of the login screen, deleting any text I put, not allowing me to right click. And I'm oblivious to what the reason could be. There's never been liquid spilled on it, dropped or anything, so I have no idea as to what it could be. I included a video to show you exactly what I mean.
(Trying to log on)

(If I'm able to log on this is what it's like)

 

[JohnDS]

What happens if you safe boot holding down the shift key?

 

[Auzzyy]

Same thing happens

 

[chown33]

My first guess is a Bluetooth keyboard nearby that has its Delete/Backspace key held down.

My second guess is a defective Delete/Backspace key on the Mac itself. It's not necessary to spill a liquid for a key to go bad; sometimes it just happens.

 

[MrAverigeUser]

My first guess is a Bluetooth keyboard nearby that has its Delete/Backspace key held down.

My second guess is a defective Delete/Backspace key on the Mac itself. It's not necessary to spill a liquid for a key to go bad; sometimes it just happens.

good idea!

The "denial" sound each time that he tries to tap a button might confirm that you are right…. but it could be every button of the keyboard...

If there is no problem with an interfering external keyboard, try to use external keyboard in place of the MBP´s keyboard.
Does the delete-button feel normal (=getting right up instantly when you leave the button)?

apple keyboards failing is not rare!

You could also try to put off the delete-button and look if there is something wrong /a crumble of bread under it or so).
On youtube there is a thousands of videos about it..., some explain in an excellent way how to take the buttons and scissor-mechanism off and how to re-assemble. Look at them.