During the game, you will unlock spells that can be a great assist on the battlefield (except for the Super Boomstick, which you unlock on the very first wave) ! All spells to damage except for the "Magic Words" spell. The list of spells Is below.

Super Boomstick: Similar to your shotgun blast except more powerful and makes more smoke when used. Does more damage then your regular shotgun but all enemies In front of you will be pushed back except for the strong ones (such as the bosses).

The Wrong Book: When used, Ash throws a book In front of him and sucks up all enemies surronding the book that have very little HP. If a enemie is not sucked up by the book, It still does quite a bit of damage. I am quite sure that you cannot suck up bosses unless they have extremely low health.

Arrow Volley: When used, Ash yells "Arrows" and a fleet of arrows hit the ground Infront of Ash. The  Arow Volley does not do much damage but does make certain types of enemies go on fire, doing continuos damage until dying!

Magic Words: When used, Ash can do two things. Either yell "Clato, Verata, necktie!" and then heal himself and all nearby allies (and wears a necktie) or yells "Claro, Verata, N&@#%!" and then random ally/allies spawn right behind Ash. The spell troop Is slightly darker than a normal troop Also, upgrading this spell just increases the chance of spawning stronger and more allies!  

Catapult Volley: When used, Ash yells "Catapult" and several rocks hit the ground In front of ash, doing quite a lot of damage! When upgraded, there will be more rocks and at mid-high levels. the stones will be set on fire, setting fire to those who survive the damage! At max level, the spell does 1906 damage!

Deathcoaster: Unlocked at wave 40, this Is the last thing that you unlock In the game (except for endless mode) ! When used, ash says "Say hello to the  21st century!" and then what appears to be a fast vechicle with a drill at the front, rams into every enemy it hits! When unlocked, It does 6000 damage, but once it does 6000 damage to any enemy, It breaks! It Is also the slowest spell, meaning that you have to wait for quite a bit before using It!