Thanks to Michelle, the song in my head is "The Bunny Song." I'm going to be singing this ALL. DAY. LONG. I just know it. I am powerless over "The Bunny Song" though I must say, I like the "New & Improved Bunny Song" much better.
And contrary to that old wives' tale, singing the song in your head out loud to clear it out does not work. It just annoys the people around you or spurs them to sing along.
If it weren't Lent, I might have to seek revenge by mentioning some of my most pestiferous earworms as:
"Think" by Aretha Franklin, as performed in "The Blues Brothers"
"Walk Like an Egyptian" (The Bangles)
"Bad, Bad Leroy Brown" (Jim Croce)
And that song about the three little fishies and the mama fishie too, who swam and swam right over the dam. (Boop boop diddum daddum waddum, choo!)
But it's Lent, so I wouldn't do such a thing.
What song's in YOUR head?