While traveling trough farm land the PCs come upon a merchant sitting on a wrecked wagon without a mule attached to it, hid face burrowed in his hands. He explains that he was robbed by petty goblins, unable to defend himself he had retreated. He asks the PCs to help him retrieve the mule before the goblins roast it, as a reward they may keep his goods. How hard can it be?
What if casting magic changed (for a few hours or days depending on the strength of the spell) the colour of the skin of the spellcaster? It could lead sadly to a very racist world to rp in.