When you have a game as massive as Hearthstone it is of the utmost importance to have consistency between the various cards. Unfortunately, that's not exactly the case right now, and cards with very similar text can perform their actions in wildly differing ways. Not exactly ideal for a card game that prides itself on accessibility.

As such, I am very glad to say that Blizzard will be fixing some of these inconsistencies in the next update. For example, using a Stampeding Kodo to kill a Mad Scientist will no longer pull a Mirror Entity that immediately copies the Stampeding Kodo, purely because the Stampeding Kodo had already entered play before the secret was even active. In other words, under this new system you will no longer need to remember obscure interactions and combos since the effects will play out exactly as they are written!

If you're currently confused and not sure what all of this nonsense is even all about, I'd recommend going to the official blog post that came alongside the announcement. It is a highly detailed article, so make sure you give it your full attention or you're going to leave even more confused. 

On the other hand, if you prefer a more visual approach, you'll find the most recent developer update right below. It doesn't go as in-depth as the above mentioned article, but it does give a couple of visual examples of the new system in action, so it should prove quite useful regardless. Have a look:

There is currently no release date set for this update, but you can expect to see it arrive in the very near future. Hopefully it will bring with it a fancy new Halloween event as well!