Question 1240: Bros before hoes

X; one of the most well known compositions in the world, was originally known as "Aboveground". It is one of the six themes composed by Koji Kondo, however, only this one is renowned. The music has a calypso rhythm and was originally played on the piano accompanied by steel drums. Today, however, most of it is synthesized to suit the purpose and is mostly found in 8-bit or 16-bit format.

Name X

Hint:

A is a soft, malleable, poor metal. It is also counted as one of the heavy metals. Metallic A has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed to air. A has a shiny chrome-silver luster when it is melted into a liquid.

A, at a certain exposure level is poisonous to animals.

A is known as B in Latin.

The hint is B.

The answer is the Super Mario BRos. theme.
A= Lead B=Plumbum; clue being that Mario is a plumber.