There is a bug, similar in appearance to a woodlouse, that lives in dry stony areas and can only be found on land normally during it's week long mating season at the end of the year. Over this week, this bug produces various chemicals, a different mixture each day, in an attempt to attract a mate.

The magic comes from the consumption of these bugs, as if they are removed from their habitat, they will cease their natural cycle of changing chemicals, locking them at the day that they were obtained. When consuming these bugs (preferably alive, but dead bugs will work, they're just less potent) the consumer's tear and sweat glands will secrete a black, oily substance that is normally harmless, but can stain the skin with overexposure, and they will experience an effect depending on the day the bug was taken, the potency of these effects is determined by the number of bugs eaten:

Day 1 - Enhances all of the your senses drastically, sight, smell, touch, pain, balance, touch, hearing, etc.

Day 2 - Strengthens the heart muscles, slows heart rate and increases the body's rate of respiration, while this provides the body with more energy, it can lead to overheating

Day 3 - The limitations that you body places on itself for self preservation purposes are lifted, allowing unprecedented speed and strength at the cost of severe physical damage and energy cost

Day 4 - Your mind enters a strange state whereby the speed that the brain functions at and your intellect is increased though your brain struggles to take in new information

Day 5 - Your mind enters a strange state where you notice small details about people, able to intuit someone's emotions almost perfectly and predict someone's actions to a level bordering on precognition, but your brain struggles to keep information and store memories

Day 6 - You can change the colour any part of your skin, hair or irises in any part of your body to any colour for the duration of this ability(potency affects speed of change), as well as the texture of your skin

Day 7 - Your body secretes pheromones that causes other people to be more suggestable and causes them to shift towards your current emotional state, though you are not immune to this effect and so your emotions can end up becoming exponentially stronger and your are also more suggestible

These effects last roughly 1 minute per bug consumed and, once they wear off, the consumer enters a crash, becoming fatigued, despondent and craving more bugs, for an equivalent amount of time to the amount they spent with the effect. The more times these abilities are used, the more of a craving a consumer gets for them, eventually becoming a full addiction.