Pick one slot
Treat each mutation roll as a single trial. Track the outcomes on a scratch pad so you can confirm when the 0.50% Prehistoric Shell probability is being met over hundreds of attempts.
Triple roll math
The Triple Mutation Roll gamepass triples the rate of acquiring legendary or mythic genetic traits, but it also triples the cash cost per roll. Budget accordingly.
Crafting the top aura
Extinct Leviathan crafting requires 3x Prehistoric Shell. Plan your mutation grinding around saving three Prehistoric Shells before attempting the aura fusion.