The Worms Crawl In, Worms Crawl Out

A different version but still pretty gross

Whenever you see a hearse go by, you may be the next to die.
They'll wrap you up in a big white sheet and throw you in a hole that's 6 feet deep.
Everything's fine for a week or so and then your nose begins to grow.
The worms crawl in, the worms crawl out, the worms play pinochle on your snout.
Your stomach turns to an icy green and pus shoots out like white whipped cream.
You wipe it up with a slice of bread, and that's what you eat when you are dead.

Here is another gross version if you want

Now don't you laugh when the hearse goes by
You may be the next one to die
They wrap you up in a dirty old sheet
Then lay you down about six foot deep
Then all goes well for about a week
Then all the worms begin to creep
The worms crawl in the worms crawl out
The worms play pinochle on your snout
Your guts decay, your chest caves in
And out runs pus like fresh whipped cream.

A Rhyming version

Oh, don't you laugh when the hears goes by,
For you may be the next to die.
They'll wrap you in a bloody sheet,
Then drop you in a hole 6 feet deep.
Then all goes well for about a week,
Until your coffin begins to leak.
The worms crawl in, they worms crawl out,
They play pinochle on your snout.
They eat your eyes, they eat your nose,
They eat the goo between your toes.
Your stomach turns a mossy green,
And pus runs out like whipping cream
And there you are, without a spoon.
But I brought my straw! Slurp!