Prior to the announcement of the album, Donald tweeted and retweeted the term “Roscoe’s Wetsuit” a lot. At first, the term seemed kind of random and irrelevant, but looking at in the context of “Because The Internet”, a couple of ideas make sense. Early on in the script, there is a conversation between SASHA, a girl the boys meet at the beach, and THE BOY, that gives us a good idea of what it could mean

SASHA: You goin in?
THE BOY: Don’t know yet
SASHA: Then why’d you put on your wetsuit?
(“…roscoe’s wetsuit”)
THE BOY: Everyone else was

Notice how the script mentions “Roscoe’s Wetsuit” after SASHA asks THE BOY the question? Could it be a symbol of how THE BOY is unsure of his place (“unsure if he wants to go in the water, but in a wetsuit because everyone else is”) in life, just as he is unsure of the term which continues to be mentioned throughout the script. When THE BOY wakes up in the hospital, this is the conversation he has with the nurse

WHITE GUY NURSE: You’re friends brought you in-
THE BOY: They’re not my friends
WHITE GUY NURSE: I don’t think they’d like you saying that
THE BOY: Doesn’t matter. It’s the truth. But also, they know. We’re not friends. There’s a mutual benefit to our relationship, but I can’t trust them for shit

This kind of emphasises the point about THE BOY not really knowing his place in life

The alternative is that it’s a symbol of how things on the internet affect people and cause people to “tweet” and “retweet” something they don’t truly understand. When the term was being thrown around on Twitter, no one knew what it meant, but people still tweeted and retweeted it nonetheless. [Props to severlyoverdressed] A few lines in the closing track “II. Life: The Biggest Troll [Andrew Auernheimer]” seem to support this

Never forget this feeling, never gonna reach a million
Eventually all my followers realize they don’t need a leader
Stay on your own shit, fuck what these clones think
Just remember that you the shit, but act like it don’t stink

The line seems to imply that we don’t need to be tweeting and retweeting what others are saying. Donald (“the leader”) wants his followers to realise they don’t need him, and should “stay on their own shit” and ignore what the “clones” think/say/do

I just get the information retweeted or say it sucks

For this line, Rap Genius sums it up perfectly: “He’s just passing on what others are saying. He’s just a vessel for culture. Instead of creating culture the internet just enables people to respond and pass on culture, rather than create it themselves.”

I think this is the best theory for what Roscoe’s Wetsuit is. That or THE BOY is actually called Roscoe and his wetsuit is fucking dope

Last thing on the wetsuit: on Tumblr’s IRL Childish Gambino feature, which features a real-life recreation of his characters bedroom, there is a wetsuit beside the bed. Interesting. Is THE BOY’s name Roscoe?