@Gravislayer - Magic is cast by thought, though it can be channelled through artefacts (or in most wizards' case, a staff). If the wielder loses focus, or is unsure of how to cast a spell. it usually backfires. Sometimes it just doesn't work. It's different from spell to spell, depends on the element in question. (The more volatile elements react more violently. Fire, for instance, would most likely set the caster ablaze)