This is how Phil and Lil play dress up in Dotted Line Girl and Spitball Boy to the Rescue.
Optimus Prime: [narrating] I have witnessed humans play superheroes before but never how my two young friends Phil and Lil did. They wanted to help us protect the world from evil but everyone thought that they got in the way. But, when we were in danger, Phil and Lil came to our rescue calling themselves Dotted Line Girl and Spitball Boy.
[We zoom in on Planet earth as the title goes by. On the planet's surface, Phil and Lil are putting on superheroes costumes]
Phil: We are... Spitball Boy!
Lil: And... Dotted Line Girl!
Phil: So, who shall we help first, Dotted Line Girl?
Lil: I don't know, Spitball Boy.
[The two super babies run off to search for people in distress]
Phil: Uh-oh, Dotted-Line Girl! Look! It looks like Percy is about to crash into those trucks!
Lil: Oh, no! You are right, Spitball Boy!