I'm going to make the first part a page with all the theories on them so it'll be easier to read. However, as new theories or info surfaces or is revealed I'll make new pages for them. 

Skydoesminecraft's roommates series season 3 episode 5 

In this episode Red is working down in his lab and ends up setting it on fire. On the floor is some creation covered in "color" or "paint" it contains various different colors like yellow, blue, purple etc... The creation crawls on the ground begging Red to kill him to which Red complies of the creatures wishes and shoots him. Barney and Sky rush down and ask Red what happened on the floor appears to be purplish paint. Red said he was just researching and Barney later questioned if it was blood to which Red says no. 

It's a bit frightening that Red killed someone even though it begged to die. And it makes me wonder about some things. In one episode apparently Bread Vacktor was mentioned to be Red's clone. And Yellow said he was born in a factory. Perhaps Yellow isn't a robot and was simply created in a similar way to the creature that Red killed. There still however is a possibility that Yellow is a robot. (Which I hope he is because I like the Yellow the robot theories) 

Many people believe Red was trying to recreate Magenta Vacktor who was according to Red andGreen  a science experiment. People have commented saying Magenta is a similar to color to Purple maybe that's why Red had a machine that said warning room contains high density purpleness, but I'm not quite sure. 

One things for certain there is much to be explained about Red and the rest of the Vacktors. 

WHAT I THINK I HEARD PURPLE'S MESSAGE say 

Oh Red it is time I will return this time (terrifying) and this time Magenta was the first so prepare (we will be) I will strike when least expected and trust me you will be (effected or effective) so think to yourself was it worth it? Because I sure don't be afraid human for I am inside you (I  heard "beside" or "I am science") I will take Red ("and the rest" or "into rest") for they never saw me (that I'm that I'm) -repeats a few times- 

The first part Purple basically tells Red that's he's going to come back and he won't expect it he also admits to killing Magenta. 

If they are saying effected than that means Purple is most likely controlling them and I mentioned that in another theory there's pretty good evidence or at least what appears to be evidence to support that. If Purple said effective then that means Red may have some sort of power that Purple wants. In a Hello Neighbor hide n seek Red made jokes about lagging someone's computer saying he was a powerful human being. I don't if that has anything to do with this but it's worth noting. Purple may also be talking about Yellow being effective since Yellow has super powers. 

So think to yourself was it worth it? Was what worth it? Did Red do something that caused Purple to become angry or to be this way? 

Because I sure (and don't may have been included with this or with be afraid human) I personally believe Purple is saying "because I sure don't" 

"Be afraid human" or "don't be afraid human" the don't part wouldn't make sense because it's pretty clear Purple wants to destroy Red it literally says so in the description. Some people believe when Purple says be afraid human he's talking to Red and some think he's talking to the audience I'm not quiet sure who he's talking. (He mentions Red's name so if he was talking to Red he'd be speaking in the third person) 

"For I am inside you" or "beside you" Inside you makes sense if the Purple controlling them theory is true which I talked about earlier. Beside you also makes less sense. Purple could mean it literally as if he is literally near the Vacktor's but it is likely untrue sense he later says "for they never saw me" why would he basically repeat his meaning? Beside you probably doesn't mean beside you as in on the same side since Purple wants to destroy Red. So Purple most likely said I'm inside you.

I also thought I heard "I am science" and this make me ponder. What if Purple was a scientist as well as Red, and Purple is angry at Red. Maybe Red took credit for one of his inventions or Purple is jealous because Red is a better scientist than he was? 

I sill take Red "into rest" or "the rest" If he is talking about the first one then it seems he just wants Red to die, if he's talking about the second one he wants all the Vacktor's he did mention earlier Magenta was the first...

"For they never saw me" was Purple secretly hiding? Was Purple hidden in videos or something? This sounds like Purple was spying on the Vacktors or maybe it relates to the "I am science" maybe Purple was never appreciated and wants revenge on Red because he was? 

"That I'm" it sounds like Purple is about to reveal who or what he is? Maybe Purple has a secret or something? 

I also want to say something else if all Purple did was kill Magenta to end up receiving the "We don't talk about Purple" and Red killed Green even if it was an accident or Purple was controlling him why can't we say "We don't talk about Red?"