DISCLAIMERS: Since I have collected every spell in the mod (future spells not included for obvious reasons), this contains spoilers. Read at your own discretion.
This only contains magic related information. It does not contain all offensive/defensive interactions used by creatures in the mod.
More will be added as time goes by.
Spell Levels
Apprentice spells have three levels, which will be referred to as A1, A2, and A3.
A1 allows the unicorn to only use the spell when directly attacking an enemy; the spell can not be used when the unicorn is fleeing, for example.
A2 allows the unicorn to target an enemy even if he or she is not attacking it.
A3 comes with the benefits of A2, but at a half-rate cooldown.
Adept level spells don't have any levels, instead automatically coming with the benefits of A2.
Also, apprentice spells that target the caster or a friendly (such as Steadfast Ward) have slightly different rules. A2 halves the cooldown of A1, and A3 halves it yet again.
Your Unicorns and Magic
Any unicorn is capable of learning A1 spells; however, regular unicorns only have the capacity to learn from one school. For example, if a unicorn decides to learn Pain, a destruction apprentice spell, he or she can also learn Fever and Sunder but can't learn Bind, an alteration apprentice spell.
However, this changes when a unicorn with an apprentice-level cutie mark enters the equation. All apprentice-level unicorns are capable of learning A1 spells from an additional school as well as A2 spells from their school. For example, a destruction apprentice can learn an A2 apprentice spell from destruction as well as being able to learn A1 spells from an additional school like alteration. Be careful though: once the unicorn learns from the other school, the effect is permanent; the unicorn can't change the school into something else.
Adept-level unicorns can learn A2 spells from all schools, as well as being able to learn adept spells from their school AND learning A3 spells from their school.
Master-level unicorns can learn master spells, adept spells from all schools, and A3 spells from all schools.
A warning: unicorns MUST have their horns to cast magic; if an enemy cuts it off, the unlucky unicorn will never cast magic again. Common sense should tell you that, though.
ANTIMAGIC
Some creatures (and some cutie marks) have a syndrome class called ANTIMAGIC that prevents magic from working on them.
There are two ANTIMAGIC types, apprentice and adept. Spells are blocked if the spell's level is equal to or higher than the creature's ANTIMAGIC level.
In the cutie marks guide below, apprentice cutie marks get ANTIMAGIC_APPRENTICE, and adept cutie marks get ANTIMAGIC_ADEPT.
Note that ANTIMAGIC creatures are not targeted by spells; thus, your unicorns will not waste time on them.
Also, the elusive magic master cutie mark has ANTIMAGIC_MASTER, which blocks all spells.
All spells are categorized in different schools. Note that while all unicorns can learn apprentice spells, a unicorn must have an adept-level cutie mark for their school to learn an adept spell, and a unicorn must have the master-level cutie mark to learn a master spell.
- means apprentice, * means adept, and ^ means master. It also indicates that the spell can be blocked by a creature with a certain ANTIMAGIC tag, i.e. the spell Bind can be blocked by a creature with ANTIMAGIC_APPRENTICE.
Spells
-Bind - Changes speed, skill rolls, agility, and kinesthetic sense to 50%.
*Paralyze - Changes speed, skill rolls, agility, and kinesthetic sense to 1%.
*Time Dilation - Changes speed, skill rolls, agility, spatial sense, kinesthetic sense, and intuition to 200% as well as reducing enemy damage to 50%. Once spell effects are finished, all stats above as well as strength, endurance, and focus are changed to 80%.
^Time Stop - Changes speed to 1000% and skill rolls, agility, spatial sense, knesthetic sense, and intuition to 400% as well as reducing enemy damage to 1%. Once spell effects are finished, all stats above as well as strength, endurance, and focus are changed to 80%.
Conjuration Spells (there currently are none)
Destruction Spells
-Pain - Causes pain in all body parts.
-Fever - Causes fever, dizziness, and nausea.
-Sunder - Causes bleeding, bruising, pain, organ failure, and blood coughing.
*Torment - Powerful version of the pain spell.
*Affliction - Powerful version of the fever spell.
*Implosion - Very powerful version of the sunder spell.
Illusion Spells
-Rage - Causes the target to be not living, opposed to life, and like fighting. Also removes exertion and fear.
-Disorientation - Changes speed to 90%, skill rolls to 50%, and agility, focus, spatial sense, kinesthetic sense, and intuition to 75%.
Restoration Spells
-Healing (targets friendly) - Causes slight numbness and changes recuperation to max. Also cleans off contaminants. Target must be wounded for the spell to activate.
-Steadfast Ward - Changes enemy damage to 25%. Also gives the caster SHIELD_ADEPT, which is the same as ANTIMAGIC_ADEPT.
Misc Spells (These spells are used by creatures other than Stable citizens; your unicorns are incapable of learning them. The creature that uses this will be listed.)
Disable Robot (Steel Ranger unicorn) - Turns a robot offline, preventing them from working.
Unity Shield (All alicorns, targets self) - Changes enemy damage to 1%.
Manifest Illusions (Trixie alicorn) - Changes speed to 90%, skill rolls to 50%, and agility, focus, spatial sense, kinesthetic sense, and intuition to 75%.
Infiltrate (Trixie alicorn, targets self) - Hides from combat, preventing self from being attacked.
Teleportation Initiation (Twilight alicorn, targets self) - Allows teleportation to be used. Also prevents paralyzation (the status effect) from occurring and changes skill rolls to 1%.
Teleportation (Twilight alicorn, targets self) - Changes speed to 300% and agility, spatial sense, kinesthetic sense, and intuition to 200%.
Eviscerate (Twilight alicorn) - Causes minor internal bleeding, bruising, organ failure, nausea, blood coughing, and pain.
Gestalt Initiation (Twins alicorn, targets self) - Allows Gestalt Field to be used.
Gestalt Field (Twins alicorn, targets friendly) - Allows the 1st Gestalt propagation to be used.
Gestalt Propagation (Twins alicorn, targets friendly, spell levels 1, 2, 3, and 4) - Changes speed and skill rolls to 1% and allows a higher propagation to be used. Also removes emotion and fear. All propagations reduce damage to 10%. Propagation levels 2, 3, and 4 respectively allow Telepathic Assault, Telepathic Barrage, and Telepathic Snap to be used. The target is also allowed to use Gestalt Cage.
-Gestalt Cage (Twins alicorn) - Changes speed and skill rolls to 1%. Also adds NOBREATHE and reduces damage to target to 1%.
-Telepathic Assault (Twins alicorn) - Causes minor dizziness, nausea, and pain. Changes agility, endurance, analytical ability, focus, willpower, creativity, intuition, patience, memory, linguistic ability, spatial sense, musicality, kinesthetic sense, empathy, and social awareness to 80%. Target has a 10% to temporarily becoming opposed to life.
-Telepathic Barrage (Twins alicorn) - Same as Telepathic Assault, although dizziness, nausea, and pain are 10x stronger, affected stats are changed to 40%, and there is a 30% chance for the target to temporarily become opposed to life.
-Telepathic Snap (Twins alicorn) - Same as Telepathic Assault, although dizziness, nausea, and pain are 100x stronger, affected stats are changed to 20%, and there is a 90% chance for the target to temporarily become opposed to life.