Info from Maraforce

You can change the colour of your pet by any of the following means:
Enchanted Plushies ??? These change your pet to the costume and species of that plushie.
Potions ??? Change your pet to the costume and species of the potion.
Essences ??? These are given randomly by the Genie. These change your pet to the species indicated on the essence but it will be a random colour, but most frequently common colours (blue, red, green or yellow).
Enchanted Dips ??? Cosmonaut can award these on completion of a quest. These can only be used on pets of the same species as the dip. It can change that pet to a random colour, most often a common colour.
Feathers ??? Talon sometimes awards a feather for completing his quest. They have a very low chance of changing your pet to the colour indicated by the feather.
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Magic stats can be gained in several ways. If you have completed the Ice Caves map you can visit the Ice Caves. You can do Computer Quests in Ziranek or visit Eleka Fountain in Eleka Castle. Level 21 of each of the Temples in Simeria gives 10 Magic stats and Level 21 of each Pyramid in Kamilah gives 5 Magic stats.
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Charisma is gained from random events, randomly when your pet completes school courses or from riding Murfin Madness in Slater Park. WARNING: Pets can get sick from this ride. Do not use it unless you can afford to cure your pet. You can also gain Charisma stats from the Guillotine but you pet might lose it's head. Level 13 of each of the Temples in Simeria gives 5 Charmisma stats and Level 13 of each Pyramid in Kamilah gives 3 Charisma stats.
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If you neglect your pet, you may randomly get a warning pop up on the page as a random event telling you that you have 7 days to cure your pet. After these 7 days, your pet will die and go to the Gates of the Graveyard. You have two weeks from your pet dying to save your pet for the last time before it goes to the Graveyard and becomes a Zombie, where *ANY* player can adopt the pet. At the Gates of the Graveyard, it will cost you 50,000MP to save a pet as a Zombie and 75,000MP to save the pet unchanged.
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You can adopt zombie pets from the Graveyard in the Undying Woods.
There is also a zombie costume but it is extremely rare. You can also feed your pet a Poison to kill it then you can rescue it for a cost of 50,000mps. The poison type must match your pet. You cannot disown a zombie pet. First you must make it a different colour using an enchanted plushie, potion or costume.
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Pets can go to Jail if you do things that are illegal. Grave Robbing, overuse of Illegal Concoctions or non-payment of a Power Bill can all send your pets to Jail. Pets with the Thief job can also go to jail in a random event.
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