How did I not know about these sooner? The first is a parody of 4 Non Blondes 1993 hit, "What's Up?" by an animation studio called Slackcircus Studios (YouTube Channel), with vocals by their employees. They eventually made the original available for remixing. You can find the truncated version, featuring just the song here.
Next up is a parody video of LMFAO's "Sexy and I Know It" and it is almost as hilarious as the first. Almost. Nothing can ever really top that. Ever.
I probably enjoyed these more than I should have.