All the spells would be effective! Since others have mentioned lightning and holy based spells, the same answer will apply: a single spell will have a limited range of 3ft by 3ft and chaining Holy spells will allow a larger area to uncover. With Holy spells, the goo will also be held back for at most a minute and a half, while lightning spells will be at most half a minute though chaining can stretch it. Mixing the two types of spell will also increase time the goo is gone before it returns.