Maxwell is going to open the coffin. Equip him with the following to kill the vampire:
Round 1: Use “Stake” on vampire
Round 2: Place “Sun” above vampire
Round 3: Throw “Garlic” at vampire

Or you can simply scare off the vampire by spawning a “holy water”.

Dig out the coffin with:
Round 1: Shovel
Round 2: Spade
Round 3: Pick

Scribblenauts Remix 11-8 Cheats Hints gallery:
11-8-1-a: Open the coffin!
11-8-1-b: Equip Maxwell with an object vampires hate.
11-8-1-c: Destroy the vampire with sunlight.