Nightmare Diamond Panther 11.36 Kg

Nightmare Diamond Panther still has the 12 Carats skill:

When harvesting fruits with 12 or more mutations, there is a chance for a random pet in the garden to increase its age by +1.
A regular Diamond Panther usually has around 4–8% chance.
If it’s a Nightmare and at a high age, the chance can increase to about 6% per harvest.
The maximum total passive chance that can be stacked is around 30%.

Nightmare makes the Diamond Panther’s passive stronger and the pet slightly larger, making it better for quickly leveling up other pets. It pairs well with fruits that have many mutations and duplication pets like Giant Ant, so the age increase chance activates more frequently.