Spell combinations are the result of multiple, specific spells being cast onto the same target or area. When a new spell combination is discovered, an entry is created in the Codex (see Codex: Spell Combinations for more details).
If Grease is set on fire, it causes a Grease Fire, burning intensely for 30 fire damage every 1.5 seconds for 20 seconds. Friendly fire possible. It is easier to torch the grease with fireball, but it is possible with flame blast if it hits an enemy.
Paralysis Explosion will cause all targets within 7.5 meters to be paralyzed for 20 seconds*(target rank). Friendly fire is possible. Note that if you are too close when the two spells combine, you and your party will be paralyzed, making you an easier target for incoming enemies.
Deals (50+0.5*SP) physical damage and knocks down all nearby targets. No effect on primary target, other than immediately ending effects of Force Field / Crushing Prison. Friendly fire possible. Can be used on friendly characters suffering from an enemy mage's Crushing Prison.
Drains the caster of additional 100 mana, when the final component is cast. Duration: 30 s. Damage: (30+0.3*SP) electricity damage every 2 s. Drains amount of stamina equal to the damage dealt. Friendly fire possible.