Mulligans
General Mulligans
Draw a whole bunch of cards and get combo pieces
Aggro Mulligans
Draw while burning your opponent's board down
Control Mulligans
To avoid Polymorph effects, play Zerek alongside Reckless Experimenter and a spell, which will automatically put him in the dead pool with a spell. Same with Obsidian Statue and Test Subject, and these should go in also along with a Spirit Of The Dead so they can be shuffled back in for later. They'll still be threats on board, so they'll draw polymorphs and hexes. This is all setup so your opponent will run out of answers for Da Undatakah to finish with them with a tombstone. You can also blow a seance on one of the setup minions if you suspect a polymorph, as you only really need 1.
Get a Test Subject, Zerek, and Obsidian Statue to die, then play Da Undatakah and cast Seance on it to add another Undatakah to your hand. When Undatakah dies, it’ll summon another 8/5 and add another Seance to your hand, as well as destroy an enemy minion. You can play a Spirit Of The Dead so when your Undatakahs die, it’ll shuffle 1 cost Undatakahs into your deck, which you can draw with Bwonsamdi and play the same turn for insane value.