Quick and Easy guide on Mutant Tarn.
*Prayer drains similar to Barrows in Tarns Layer*
Gear
Melee tank gear, Karils top, tank rest. Pretty easy fight. Bring Pray pots and food.
Melee (Dogs) Safespot
Run up to him, stand in the highlighted spot before he transforms and pray mage. Dogs will be stuck beside him. Return to the spot after looting before he respawns
Range/Mage (Dogs) Safespot
Run to 1, once dogs attack, run to 2 and pray mage. Loot then run to 1, and move to 2 after dogs attack.
I'm not 100% sure what the best gear is, but works well for me.