The first encounter with the big-headed tiger. Grug throws a rock at it. It catches it and tosses it aside with a "Really?" expression on its face.
Really, every expression that tiger ever displays. After joining forces with Grug, who declares that he has an idea, Chunky very clearly looks worried to be near him. Them while helping Grug, he gets a clear "WTF" expression on his face at the tar pits. But the best one has to be when they successfully achieve flight, and Chunky's face slowly morphs from fear to an elated expression that screams holy shit this is working!
Ugga: If your father were here right now, he'd say—
Grug: (offscreen) GET OUT OF THE WAY!!!
Thunk: Wow, you sound just like him.
Both puppet shows.
"Here, hold this."
Grug's reason for trying to come up with ideas.
Grug: And...I thought it would kill your mother.
The prehistoric equivalent of "Heads or tails".
"Try hiding from it in the tall dry grass!"
During one of Guy's quirkier moments, Eep asks him how long he's been on his own. Cue Belt spreading his insanely long arms.
When Chunky appears behind Grug in the cave and his breath blows out the torch... and they both start it up again by frantically blowing on its embers, because Chunky's even more afraid of the dark than the people are.
Gran: "I was in love once. He was a hunter, I was a gatherer. It was quite a scandal."
Guy, on the coming "end of the world": "I don't mean to sound alarming here, but ARGHHHHHHH! AAAAARHHHHH! AAAAAAHHH!"
Grug repeatedly finding himself back at the place where he fell into the maze.