When you see a creature in range casting a spell using Verbal, Somatic, or Material components, you may try to interrupt it with a Reaction. The target makes a Constitution save. On failure, the spell dissapates, and the the casting Action, Bonus Action or Reaction is wasted. If the spell used a spell slot, it's not expended.
The most valuable ability as a professor in the Royal University is not academic excellence, but quick reflexes.
-Eudoria Hackett, Royal professor
Cast a spell of level 5 or lower that you can cast in an action targeting yourself. This becomes the contingent spell, expending its spell slot as well as Contingency's spell slot. The spell doesn't take effect until a chosen trigger occurs.
As soon as the trigger happens, the spell takes effect whether you want it to or not, and then Contingency ends.
You can only target yourself with the contingent spell, you can only have one contingent spell at a time, and the whole spell ends if you ever don't have the material component on your person.
See the Player's Handbook for the exact rules.
Spells casting spells seems like a bad idea. Let's try it.
-Abjurist Ovtuch Irieya moments before major arcane breakthrough
Condense a bead of yellow light at a chosen point in range. The base fire damage it can inflict is 12d6, and this damage scales normally. Additionally, every time your turn ends while the spell is active, the damage increases by another 1d6. A creature may attempt to throw the bead up to 40 feet by rolling a dexterity save, with the spell ending if it fails or when the bead hits something.
When the spell ends, the bead explodes, dealing its cumulative fire damage to all creatures in a 20-foot radius, and lighting all loose flammable objects on fire. Creatures roll a dexterity save to take half damage.
See the Player's Handbook for the exact rules.
And this is a fireball, in its static form. For the love of Lyri, DO NOT POKE IT.
-Qemuel Fridson, Royal professor
Touch the material component and an object weighing 10 pounds or less and whose longest dimension is 6 feet or less. An invisible mark is inscribed on the sapphire. Only one object can be attached to a sapphire.
As a magic action, you can speak the name of the object and crush the sapphire. The object instantly appears in your hand, crossing any physical or planar distance, ending the spell. If another creature is holding or carrying the object, it doesn't transport it, but you immediately learn who and where that creature is.
The spell is a bit costly, but there is some keen interest from applicants we're fairly sure are from the thieves' guild.
-Branson Ottewell Anderson, Royal professor
Give a willing creature truesight with a range of 120 feet.
It's all fun and games until you find out someone has been magically disguised for three years.
-Diviner Elton Elderwick
Compel a creature you can see in range to die. If it has 100 hit points or fewer, it dies, otherwise suffering 12d12 psychic damage.
When empowered, it kills another person. Unempowered, it kills you, because speaking this word universally demands immediate execution.
-Eudoria Hackett, Royal professor
Assault a creature you can see in range with intense pain. If it has 100 hit points or fewer, and is not immune to being charmed, its speed is reduced to 10 feet, and it has disadvantage on all D20 rolls except for constitution saves.
The creature must roll a constitution save when casting a spell, or the spell fails and is wasted. At the end of its turns, it may roll a constitution save to end the effect.
While we are pleased to have solved the weavecraft of this word, we cannot think of any non-psychotic reasons to use it.
-Archmage Ieliana
Overwhelm a creature you can see in range. If it has 150 hit points or fewer, it becomes stunned, otherwise having a speed of 0 until the start of your next turn. The stunned target rolls a constitution save at the end of its turns until it succeeds, ending the condition.
Uhhhhh...?
-Novice Balvur Kingshorn, one of the victims of the failed recitation disaster