Everyone has been saying that a Hydra would be a good beast so I have thought of some colors and genes for it!

This is a very long list

Colors: Green,Blue,Brown, and Red

Genes:

Poisonous blood: your pet's blood is poisonous opponents have a 40% chance of being poisoned when using bite.(10% health loss every turn)

Sharp teeth

Blunt teeth

Weak jaws

Normal jaws

Double incisors 

Poor hearing

Normal senses

Deaf

Animal instinct 

Petrifying gaze

Acute eyesight 

Smart

Slow-minded

Silly

Quickmind

Fearsome look

Berserker

Agile paws

Clumsy paws

Normal paws

Blunt claws 

Sharp claws

Artisan

Solid bones

Fragile bones

Light bones

Normal bones

Thin bones

Steel bones

Strong muscles 

Weak muscles 

Normal muscles

Dystrophy 

Normal organs 

Faint-hearted

Boiling blood

Thick skin 

Normal skin

Thin skin

Elemental vulnerability 

Elemental resistance 

Robust scales

Venomous skin

A new one: Spikes: your pet is coated with spikes rush and blow damage is increased by 30% similar to ice spikes

I might draw it later