How do you beat the duel in Superscribblenauts?

In Superscribblenauts, there are two options in which you can solve the duel at the start after being summoned by Maxwell:

Defeat with Words: Write something or summon anything which will either scare off or defeat the enemy such as 'lion', 'giant spider', 'gun'

Run for Shelter: You can also enter through Maxwell’s portal when the opponent charges for the attack