Here's a 16 or 17 round Wastewalker Shu strat that is mostly level 1 pet safe. The carry pet will take 15 + 30 + 45 = 90 non crit Mechanical damage, so the carry pet just needs like 116 HP (assuming 1 crit) health if non beast and 174 HP (again assuming one crit) if a beast, so you can pretty safely do a any non beast at level 1+ and any beast at level 2+. Luckily if you use Rematch as an addon, you can just set the team preferences to only load carry pets that match that criteria.
It does require an XT pet, so either Pet Store (preferred due to higher health) or AH gold (will work still). This strat won't be for everyone, but it is fast and pretty reliable
Team 1: 16-17 rounds (crits can make it 14-19)
- 1: Carry Pet - - Min 116 HP for non beasts (level 1+), Min 174 HP for beasts (level 2+)
2: [pet]Lil' XT[/pet] [-] (1,2,2) or [pet]Landro's Lil' XT[/pet] [-] (1,2,2)
3: [pet]Pandaren Water Spirit[/pet] [-] (1,2,2)
- - Pass > Switch to XT > Heartbroken > Tympanic Tantrum (3x rounds) > Zap until XT dies (usually 2x)
- If XT dies before Crusher, select Water Spirit and use Water Jet until Crusher dies (usually no more than 2x)
- - If XT is still alive, Zap until dead and select Water Spirit, otherwise:
- If Pounder's first round (Sandstorm), use Whirlpool
- If Pounder's second round (Rupture), use Dive
- Whirlpool on cooldown and use Water Jet until Pounder dies
NOTE: You want to ENSURE that Pounder doesn't die before the last round of Sandstorm. You don't want to have Sandstorm up for any rounds vs Mutilator for this to work. So if you crit vs Pounder, keep an eye on his HP and pass a Water Jet round if you have to.
- - Water Jet x2 and he dies.
The gist of how this works is Tympanic Tantrum will bring Mutilator down to 423 HP (or lower if it crits). Mutilator uses a shield that reduces damage by 74. If Sandstorm isn't up vs Mutilator, the Water Spirit will be able to kill Mutilator before any major damage damage is done (only a single reflected damage from Spiked Shield). If Sandstorm is up, it will take 1 extra round and Mutilator can get in 2 major hits if he follows spiked skin with Powerball. Either way, you want to make sure that Sandstorm is down vs Mutilator.
The Water Spirit doesn't suffer from the 10% accuracy debuff and can dive to avoid Pounder's first rupture (so no stun). Otherwise, stick to keeping up whirlpool and using Water Jet in between. Pounder should never get to the 2nd rupture.
There only thing two things that can screw this strat up:
1. If you accidentally kill Pounder before the last round of Sandstorm. If you don't crit on him, it won't be a problem, but if you do, you'll have to quickly decide if you need to attack or pass on a Water Jet. Shouldn't need to pass on a Whirlpool unless Sandstorm is ending and a Water Jet will kill him as it ends or after.
2. If XT is killed before Crusher dies on round 5. This can happen if both a Whirlpool crits forcing the mech round early AND the following surge crits as well. There is an extremely low chance of this (less than 1% chance).