Naru Meha and Living Death (the MP) create an infinite loop you can only quit by force-closing the game. I just came across this while I was trying to master those two cards. Don’t put them in one deck, you might regret it.
Living Death pulls Naru from the graveyard and gives it full mana. Then Naru Meha fills Living Death’s mana and Naru Meha is put into the player’s hand again. The only way to stop this is force-closing the game.
I think it would also work if you had a Naru in the graveyard and cast another one with Living Death as the first spell in your hand. Other creatures in the deck would make it less likely to trigger, but I believe it would still be possible.
I don’t remember the cards I had in hand or the exact sequence, but I assume it was like you wrote. Most likely a Naru had been killed by Nissa’s spider, so when I summoned another Naru, Living Death must have been the first spell in hand and made Naru came back from the graveyard.
Naru definitely wasn’t the only creature in the deck, it was just the only one in the graveyard.
Perhaps Living Death simply needs a confirmation box so it wouldn’t autocast. The logic behind which spells need confirmation and which don’t is something I will never comprehend, I think.
Others bugs will still appear with naru. As I said in another topic, the solution to the problem is to create a code to limit the AI of playing naru infinite times per turn. However, they nerfed the best mythic DOM card (in my opinion) and their interactions … and the problem will persist.
The infinite loops goes as follows: 1- Have a Naru on the top 3 card on graveyard (not sure if the exile effect is being applied, i once used 2 living death in a row for 5 creatures and had 0 on board if i remember correctly);
2- have a naru alive on board or cast it (helps to gain mana fast on hand); 3- Auto cast living death (need to have 2 copies) , returning dead naru to hand and killing all creatures; 4- nor that you have a new naru on hand it will be recasted, duplicating living death, filling its mana and going infinite while killing the other copy.
How to solve the issue (In my opinion): have living death’s exile effect come after killing all the board, that way no creatures can be reborn after the first living dead.