Simple way to get multiple related objects in Parse.com with Javascript?

I have a Player class. Players can have x number of Trophies. I have the Player objectId and need to get a list of all of their Trophies.

In the Parse.com data browser, the Player object has a column labeled:

trophies Relation<Trophy>
(view Relations)

This seems like it should be so simple but I'm having issues with it.

I have the ParseObject 'player' in memory:

var query = new Parse.Query("Trophy");
query.equalTo("trophies", player);
query.find({
  /throws an error- find field has invalid type array.

I've also tried relational Queries:

var relation = new Parse.Relation(player, "trophies");
relation.query().find({
  //also throws an error- something about a Substring being required.

This has to be a completely common task, but I can't figure out the proper way to do this.

Anyone know how to do this in Javscript CloudCode?

Many thanks!

EDIT--

I can do relational queries on the user fine:

var user = Parse.User.current();
var relation = user.relation("trophies");
relation.query().find({

I don't understand why this very same bit of code breaks if I'm using a non-user object.