A valid physics-enabled game object, or just an object that has "body" property
Get the root body of a compound Matter body.
Check if object is an acceptable physical object for this plugin - a Matter Body, a tile, or an object with a body property.
Duck type to check if the given object is a Matter body (because there isn't a prototype).
A union of all the types of physics objects we could have in the simulation - from raw Matter.js bodies to tiles and physics-enabled Phaser GameObjects.