Hearthpwn

pnote: a less refined take on the concept was posted a while ago over here https://www.hearthpwn.com/decks/1203210-new-apm-priest-otk-regenerate-test-subject

here we go.  7 cards. ten mana.  infinite damage. you don't have to put stonetusk boar in your deck.  are you fast enough to regenerate your opponent to death?
the base of this deck is the test subject/vivid nightmare/radiant elemental interaction that lets you infinitely duplicate things. past decks have used divine spirit, stonetusk boar and topsy turvy, but let's be real having those cards in your deck sucks! lets swap them out for real cards: regenerate, auchenai phantasm and pain or holy smite.

test subject returns spells to your hand in the order they were cast.  that was bad for topsyturvy.dec but is great for this deck because the last card we play on our test subjects is fine to overdraw.

the core of the infinite combo is to have two non-damaging regens cast on our test subject before the second vivid nightmare.  while comboing your hand may become clogged with unplayable vivids, but as soon as you start overdrawing the second vivid you played you'll stabilize, and as long as you're getting 2 regenerate at that point you net damage for each loop.

You must have 10 mana and the following cards in hand:

regenerate

test subject

radiant elemental

vivid nightmare

another of either radiant elemental or vivid nightmare

auchenai phantasm 

a spell to kill one test subject at least once for 2 or less mana (pain or holy smite)

combo like this

test subject (1 mana)

radiant elemental (3 mana)

second radiant or copy it (5 mana)

regen subject

vivid subject (6 mana)

kill subject returning vivid, regen and kill spell.

regen subject.

vivid subject (7 mana)

kill subject returning regen, vivid, regen, vivid, kill spell (5 cards)

vivid radiant elemental (8 mana)

regen x2 subject

vivid subject

play auchenai phantasm.

kill subject returning regen, vivid, regen, vivid, regen x2, vivid, kill spell. (8 cards. if you started with a full hand, you will overdraw your kill spell.  this is fine)

burn opponent for 12, or 9 if you overdrew the kill spell.

vivid subject

waste a vivid on whatever (1-4 cards in hand)

kill subject returning 4x regen, 2-3x vivid and your kill spell if your hand was empty to start.

burn for 9-12.

vivid subject. you'll have 4-5 cards in hand and have dealt 18-24 damage at this point.

kill subject getting regen, vivid, regen, vivid, and possibly a 3rd regen.

deal 3-6 damage and start doing 3 damage loops till your opponent is dead. if you started with 3 dead cards you'll have to do 3 loops to 30 them so play fast!

if your opponent is playing a slow deck and at like 70 hp or something you can incorporate an additional radiant elemental, vivid nightmare or regenate to drastically drastically boost your dps.

 

and there you go! go forth and regenerate people to death.