I found this mashups through a series of Google searches, and it starts with the familiar acoustic guitar sequence from Avicii's "Wake Me Up." Eleven seconds in, I heard a familiar voice state, "Once upon a time, not so long ago." I couldn't for the life of me figure out where I had heard that before, but a quick Google search revealed it to be from the very beginning of "Livin' on a Prayer" by Bon Jovi. But then at sixteen seconds...I was rickrolled! Yes, this mashup by NilsOfficial combines "Wake Me Up" with "Never Gonna Give You Up" by Rick Astley.
A worldwide hit in 1987, "Never Gonna Give You Up" had a resurgence beginning on April Fool's Day 2008 when various websites posted links to the song, rather than to the actual video they claimed to post. The phenomenon of directing someone to the Rick Astley video without their knowledge became known as "rickrolling." If you clicked on the mashup above...you just got rickrolled.
"Wake Me Up" features the same four chords for the entirety of the song: Bm G D A, and this repeated chord pattern serves as the accompaniment for the mashup, as well. "Never Gonna Give You Up" is originally in D-flat major/B-flat minor (the tonic floats between these two relative keys). Astley's vocals are pitched up by a half step in the mashup, so that his melody centers around D and B, which fits well with Avicii's acoustic guitar chords.
I thought I had it all figured out - Avicii vs. Rick Astley. But then at 1:16, Chumbawamba! The chorus from the 1997 song "Tubthumping" appears as a bonus chorus in this mashup. In my opinion, this part goes on for too long. "Tubthumping" is famous for being both repetitive and irritating, which are features that remain during its time in this mashup as well (1:16-2:03).
Despite this, "Never Gonna Wake You Up" has what the community considers to be the three main features of a good mashup: it is well-constructed (rhythmically and melodically/harmonically), it is funny (due to the inclusion of both Rick Astley and Chumbawamba), and although it doesn't feature a genre clash, the three songs are separated by a wide enough time gap (1987, 1997, and 2013) that their combination seems fairly unexpected.