Continuity mistake: When we first see the English guy in his car, his crates of goods are stacked askew in the back seat. After Peter's crew shoot the car several times and the car is half-wrecked, the boxes are suddenly neatly packed into the seats. Moments later, we see the boxes piled randomly again. This change happens a couple more times before the scene is over.
Continuity mistake: The English guy's car is full of crates when we first see it and when his roof is blown off but after Peter and a crewman have boarded, there are suddenly barrels in the car too.
Continuity mistake: In the scene when Peter tries to get the bullfrog out the window there is a dartboard but when he walks in it wasn't there.
Other mistake: Joe Swanson is colored incorrectly. His color scheme is apparently the same as Peter Griffin's when looking at his skin color and hair. It is fixed shortly afterwards. (00:11:54)
Chosen answer: It's a real song called "Elvira". Originally by Dallas Fraizer in '66, however, this version seems to be the Oak Ridge Boys cover version. However, the mega lesbians skip the verse and just sing the chorus after the opening line.
Bishop73