Werid Online virtual word game?

That basic style of game feels like many Virtual World games I played in the 2000s.

Could it be Moshi Monsters? The monsters look alien, and there is a Music Islands area of the game that could contain musical instruments. You can buy pets, known as "Moshlings", but none of them look like a platypus.

If it's not, we'll need more information, like the approximate year you accessed it, how it looked, and any other gameplay details you can remember. It's okay if you don't remember everything about it.