There's a monster under my bed

There's a creature dwelling underneath,
he tells me that his name is Rhys.
I tell that it is not so,
but he tells that it is and that I know.

He came out last night to tell me tales,
to tell me of his time in Wales.
I tell him that I've been there too,
he smiles and nods as he scares me through.

There's a monster living under my bed,
and I know that he's inside my head.
He looks like me,
and has my name.
And he tells me that we are the same.
Though why he should appear to me,
is beyond my comprehension.
And though I am no expert,
his lack of fangs defies convention.