Like 'I Met a Bear'. Repeat short line after leader, then everyone sings verse together.

The littlest worm
I ever saw,
Was stuck inside
My soda straw.
everyone: The littlest worm I ever saw, was stuck inside my soda straw.

He said to me,
don't take a sip.
For if you do,
I'll surely slip.
everyone: He said to me don't take a sip, for if you do I'll surely slip.

I took a sip
and he went down
right through my pipes
he must of drowned.
everyone: I took a sip and he went down, right through my pipes he must of drowned.

I coughed him up
and he was dead.
I buried him
in my counselor's bed.

He was my pal.
He was my friend.
But now he's gone
and thats the end.