Can you guess what it is based on these clues?

It’s not an animal that is known to be used.

It’s not like they are a muse.

But they’re a funny-looking creature,

And are full of all these unique features.

You wouldn’t want to hang with them for leisure

Because of their poisonous beaks.

They may live in creeks and swim around in peace.

The only mammal to lay an egg

It’s unique and unforgettable.

Like nothing you’ve ever seen before.

Can you guess yet what animal is my favorite?

If you can’t I’d suggest you look down under

From what I can remember.