This is Duck, Duck, Goose but in Spanish.
First form a circle sittling down and have one student go around touching the heads of the other students saying "Pato, Pato, Pato." When he/she touches another students head and says "Ganso" then that student gets up and chases the other student around the circle until they sit down in that students place. If they are tagged before they have a chance to sit down then they sit in the middle until someone else is taged to take their place.