I got the dog and sausage courier on my second spin. Which is a great courier! But I already have one.
Once that big invoker reaches the rage state around 1/3 heath or so it seems impossible.
Saw the video of the guys that beat it. They used Techies and set up a trap of a million remote mines and they all stay away from Invoker while he's doing this. Apparently, you don't need to distract him. You keep him from spamming the summon creeps by not attacking him. Then, they lure him into the trap and insta-death!
We almost had it with the 4 stack I got queued with. Got him to like 15% health and he would just refresher combo everyone. We tried to take turns tanking, but you can't be revived if there are any summon creeps anywhere near you. :|
[edit]Looks like they patched that strategy out: * Remote Mines now last 4 minutes in Dark Moon