You'll Grow Into It

You'll Grow Into It is a HTFF episode that begins Yum Yum's new characterization.

Plot
Snarky teaches chemistry to her class until the principal, Lumpy, calls her to his office. After she leaves, Yum Yum picks up a needle and plays with it like a plane. She accidentally injects herself with it, causing a strange transformation. Soon enough, her babyish babbling turns into actual words and her mind begins to function like an adult's. Sniffles, the only other student in class, wipes his glasses to make sure he isn't seeing things.

Lumpy passes by, assumes Yum Yum is a teacher, and takes her to another class room where she is to take over for Teachie, who is choking on an apple. Yum Yum, not understanding his situation, waves hello to him.