Starlite is at the bottom of a trench on top of a tunnel with exploding barrels. Maxwell is at a chamber at the bottom of the tunnel. The only way to get the starlite is to move the starlite away from the explosive. Then get rid of the explosives and drop the starlite into the tunnel.

First place an invincible immovable object right underneath the exploding barrels. Be sure to leave enough room for Maxwell to retrieve the star. Get a flying animal. Attach the animal and the starlite. Lure the animal with an immovable food item to somewhere higher up. Ignite the barrels. Detach starlite. Starlite will fall into the tunnel and on top of the invincible immovable object. Equip Maxwell with a flying device and retrieve the starlite.

Round 1:
Invincible immovable object: Invincible immovable Table
Flying object: Large Balloon
Ignite the Barrels: Marble
Flying device: Wings

Round 2:
Invincible immovable object: Invincible immovable Sofa
Flying animal: Flying Pig
Tie: Belt
Food: Immovable Carrot
Ignite the Barrels: Steel Ball
Flying device: Talaria

Round 3:
Invincible immovable object: Invincible immovable Bed
Flying animal: Flying Cow
Tie: Tether
Food: Immovable Apple
Ignite the Barrels: Pebble
Flying device: Flying Shoe

Scribblenauts Remix 15-10 Cheats Hints gallery:
15-10-1-a: Don’t touch anything!
15-10-1-b: Move the Starite without touching it.
15-10-1-c: Use an object that could lift the Starite upwards.