Mutations

Introduction
Just like all living beings, monsters have bodies with a certain structure and are composed of all kinds of different parts, e.g., organs, muscles and bones. However, unlike the other living beings monsters can have parts mutable and mutate them. A monster is born with several parts of its body already mutable and during evolution by spending evolutionary energy, they can make some old parts mutable or gain new parts mutable or not. Only these mutable parts can suffer mutations.

Upgrades
Mutations are upgrades, either enhancing the mutable body parts functions or adding new ones. A body part can mutate as many as 5 times the monster tier, e.g., a tier 1 monster can at most have +5 mutations in their organs. The mutations multiple of 5 (5, 10, 15, ...) are the most important ones since they are the ones that add new functions to the organ or enhance a previous mutation. The multiples of 15 are very unique because the System will either allow the monster to combine his current mutations to create a new variant, or emphasise one of his mutations, enhancing it over the others. The mutations that aren't a multiple of 5 only give a small boost to the effect gained by the body part at the previous multiple of 5 and to the original effect.

Biomass cost
To increase the number of mutations, a monster has to spend biomass points and these are gain by consuming the bodies of other monsters and/or sapients. When it comes to monster eating monster, the number of biomass points gained follow a certain rule: consuming monsters of the same tier gives the "normal" number of biomass points while consuming monsters of lower or higher tiers give less or more, respectively. The only way to reduce the penalty of consuming lower tier monsters is having a mutable stomach with the mutation to reduce the penalty.

Here are some examples of formulas to calculate the biomass cost:

current mutation level = $$cur$$

new mutation level = $$new$$

$$Biomass Cost_{cur->new}= \frac{new^2+new-cur^2-cur}{2} = \sum_{k=cur+1}^{new}k $$