the.com/mashup
Two songs walk into a bar; one DJ refuses to let either leave alone.
means A creative work made by blending two or more existing pieces — typically a song's vocals over another's instrumental — into one cohesive new thing.
from From the verb to mash, meaning crush together, plus up — old kitchen slang that jumped into 2000s studios when bedroom producers started welding acapellas onto foreign beats.
Breakout momentThe Grey Album fused Jay-Z and the Beatles, 2004.
Beyond musicWeb mashups merge data feeds, like maps plus listings.
Legal gray zoneOften technically infringing, rarely sued, widely beloved.