I'm hoping it's just a wav file of Dominic's singing on MI3.
"For those cold, dark shipboard nights,
We've got boxers, briefs, and tights
Made from cotton, silk, or satin,
In styles Anglo, Dutch, and Latin,
When you sail don't take a chance
Wearing nothing 'neath your pants!
Trust...Silver's Long Johns! (They breathe!)"
(Thanks ScummBar!)