At a random candy store, Marco showed Star a couple of jawbreakers as three dudes tried to break in. "Star, these are jawbreakers, named as such for their hardy nature." Marco explained, giving Star an idea.
(Later, during a fight with Ludo and his minions)
"Go, jawbreaker!" Star shouted.
Star took out a jawbreaker and threw it at Ludo's army... who simply ignored it and ran after the duo. "Why didn't the jawbreaker work?!" Star questioned in shock.
"It's not a weapon, it's food!" Marco snarled.