Studying these arcane texts for so long makes your eyes go square and you're fed up with all the spelling mistakes. You've developed a knack for spell checking so much you're incorporated it into your spell book. Those spells that might be spelt wrong now have a chance to develop their new properties.
One day you were writing down the mechanics of Darkvision you didn't realise you wrote down Barkvision, before you knew it when cast, everything looked like trees, completely useless spell, but through trial and error you have developed some tweaked spells of your own.
Some Examples:
Clair 'noyance - annoys Clair
Hear Metal - lyrics by any songs being played are translated into Infernal
Smote - casts "Smite" on a target, three rounds ago
Cone of Sold - wins any auction occuring within cone's area
Chill Couch - summons a chill-ass couch to hang out on
Circle of Powder - summons powdered donut (bonus when cast in conjunction with Divine Flavor)
Barkvision - everything looks like trees, completely useless
Comments