So you play Lucentbark, then Deranged Doctor and later Recurring Villain. They die in the order they are played. Then you play Undatakah. The Undatakah gains the deathrattle: Go dormant. Restore 5 health for this to awaken. Restore 8 health to your hero. If this minion has 4 or more attack, re summon it.
And If you have Lucentbark dormant, every time Undatakah dies, he brings a clone and revives 4/8 Taunt.
It might work once, but after that Da Undatakah will no longer have his Battlecry activated; resurrecting him is not akin to playing him. This means the clone will no longer have the Deathrattles, so the cycle cannot continue.
I think it got proved that "Goes dormant" actually doesn't put the minion in a "dormant" state but summons a specific token to replace it. If your Undatakah gets the deathrattle from Lucenbark, it will actually summon a dormant Lucenbark.