La Potion des Petits Magiciens

To your cauldrons, magicians! To win, gather red, purple, green or yellow ingredients and concoct as many potions as you can...

Choose a player and ask him for ingredients of a color of your choice. Does he have any? Great, keep playing. Don't have any? He answers "Cauldron!", you draw a card and your turn ends. When you've collected 4 ingredients ... abracadabra! You've just created a potion! Seahorse shells, toad pustules and unicorn horns will come in very handy.