Jackson 5 vs Nirvana Mashup
Also, while I'm posting music videos, do you realize that Kidz Bop did Ke$ha, master of talking rather than singing? They changed "Before I leave, brush my teeth with a bottle of Jack" to "brush my teeth and then I go and pack." I can link you the audio track but I'll let you know that they cut out the whole middle part.
Someone also went and amped up the creepy by mashing up their original sexualized videos with the kids bop audio. They change the lyrics around, but somehow "we'll melt your popsicle" stayed in California Gurls.