Cavin:(Counts his fingers for a moment) That sounds familiar.
From the very first episode:
"Is it true that humans eat Gummi bears?!"
That entire scene is hilarious. The bears are gathered around an unconscious Cavin, arguing whether they should help him or leave him be, like a bunch of kids who have found an injured squirrel in their yard. When they see he has a Gummi medallion, they start passing it back and forth while it's still tied around his neck, not even noticing when the kid wakes up, since he just lies there, staring at the weird creatures surrounding him, until he bolts up, beaming with joy over finding the legendary Gummi bears. They all promptly run for their lives in terror.
Cubbi and Sunni imitating the adults after they figure out how the Changing Hat works in "A Gummi By Any Other Name." This is later topped by Igthorn's reaction after Zummi casts the spell that makes his voice sound like a chipmunk on helium.
To lure a mermaid into a trap in "Water Way To Go," Igthorn tosses Toadie into the river.
Igthorn: Pretend you're drowning!
From the series finale, when Igthorn tries to unlock the Great Book with a hammer and chisel: