even though micro mummy is disabled as a tier 1 to buy for now, a shifter zerus i had turned into a micro mummy in a game i had this afternoon which shouldnt probably happen
reflect over your own statements and you will find the solution 
Micro Mummy hasn’t been removed. An issue with a crash caused by tripling Micro Mummy has been fixed.
My bad. I was reading the wrong patch notes.
Actually that is not correct, the fix did not fix everything and Micro Mummy was deactivated a second time shortly after the “fix”:
I am pretty sure I saw on Twitter that the full fix will be released in the net content patch, that is still upcoming. Can’t find the source right now though.
Oh, my bad…
Actually, come to think of it, I think I noticed a Micro Mummy being spawned from another card during battle. I didn’t take much notice of it at the time.
I think it may have been just disabled from purchasing from Bob’s Tavern, similar to how some cards can’t be drafted in Arena, but still can be summoned or discovered by effects.
The problem with this, using Zerus (and to an extent, Nat Pagle) you could eventually find 3 Micro Mummies and crash the game.
more specifically, it was removed from the tavern (aka from buying) not from the game. its a very narrow scenario to generate 3 micro mummy at the same time.