This is an interesting idea. I agree with Santar and Coshade that it depends on our interpretation of "one of your creatures". If we take that to mean a creature that you control, then you could put it on a Mind Controlled creature. This could have the weird affect though that if the creature gets free of the Mind Control before the Chant of Rage is destroyed, then the Hate token would end up on an enemy creature and thus not be destroyed when Chant of Rage is.
I'm pretty sure that that interaction is not intended. But then there's also the weird interaction where if we interpret it as a creature you own, you could put it on a creature your enemy has stolen from you with Mind Control. That isn't really desired either. You could also argue that it should be limited to a creature you both own AND control.
I'm honestly not sure which of these three positions I would promote, nor am I positive if there's ever been a ruling on what "your" means in the past. I want to say it means something you control, so it would work exactly how Kaarin suspected, but I honestly don't know for sure. The safest answer, I think, is the third option requiring both owning and controlling. Does anyone have previous examples of similar wording?
I have found various uses of "your" on the spell cards. There are:
Your Mage*
Your spellbook
Your discard pile
Your opponent
Your zone
[type of spell] your mage controls
Your mana supply
Your choosing/your choice
Your spells
Your Challenged enemy
Your next attack
Yourself
Your effect roll
Only Chant of Rage refers to 'your creatures', rather than 'friendly creatures' or 'creatures you control'.
I would like to think that 'your creature' must mean something other than 'creature you control', or else the latter phrase would have been used since it is commonly in use on other cards.
The only thing I can think it might mean is 'a creature that came out of your spellbook' (i.e. a card you as a player own). The only rationale I can think of for this is that if the creature you Mind Control is destroyed, it does not go onto your discard pile, but the opponent's, since it is their card after all, and not *ahem* yours. The phrase 'your discard pile' is used several times to distinguish between the two piles.
There is a wide inconsistency in usage between "your mage" and just "your". They clearly almost always mean 'your mage' rather than 'you the player' (or else their would be interesting connotations for spells like Smite), but I argue you have to make exceptions for the more metagame concepts of 'your creature' and 'your discard pile'.
All this is a long winded way of saying "I think Zuberi's second theory is probably right, odd as it may seem".
But who knows? This is a very interesting question.
*in passing I note that the Ivarium Halberd refers both to 'this mage' (being the target) and 'your mage' (being the caster) - thus in theory if they were playing together in a variant match an arena mage could cast it on to an academy mage, who would thus gain one attack die more than if if they had cast it on themself. This contrasts with similar Academy weapons, such as the Johktari Hunting Knife, which use the term 'this mage' throughout.
