Bolt trying to melt a lock with his Eye Beams... in the real world.
Bolt: If I stare at this lock long enough, it'll burst into flames and melt. Mittens: Now I'm concerned on a number of levels.
And later on when they're in the animal control truck (but in different compartments) and Bolt is still convinced he can use his powers to escape.
Mittens:You can't, Bolt! You got nothin'! No super strength! No super bark! *realizes Bolt's not responding* And no heat vision. (Cut to Bolt staring at the door so hard you think something in him is going to burst.)
The scene where Mittens tries to threaten Bolt with a Styrofoam packing peanut, because Bolt has become convinced that Styrofoam robs him of his powers.
Not to mention every line Rhino says.
This bit from the scene where Bolt and Rhino rescue Mittens from the animal shelter. Just the casual air with which Rhino says his line:
Bolt: There's a guard. Rhino: I'll snap his neck.
Then later on when Rhino and Mittens have just arrived at the studio, Rhino sees one of Dr. Calico's 'henchmen', and runs towards him screaming various death threats. The guy however, only hears a bunch of squeaks, and thinks that Rhino's cute.
Rhino:I WILL BEAT YOUR PANCREAS WITH YOUR SPLEEN AND-
''cut to outside of ball, only able to hear Rhino's high-pitched squeaks*
Henchman: Aww, aren't you the cutest, with your little whiskers....
And from shortly after that, when Bolt performs the actual rescue:
Mittens: Bolt? What are you doing here? Bolt: I'm busting you out! Mittens: You... you came all the way back here, for me? Bolt: Yeah. Mittens: But how'd you... I mean... you don't have any super powers! Bolt: I know. Mittens:(surprised) Really? Bolt: Yeah. Mittens: Wow. Crazy day for you, huh? Bolt: It's been a lot, yes, it has.
Mittens' reaction after Rhino's initial introduction, and suggestion that he and Bolt could be twins.
Or when Bolt hits the perfect "Cute Doggy Face" under Mitten's tutelage.
And then when the guard comes in to check on them, he sees one of the dogs nomming on Rhino's ball.
Rhino: Initiating escape!
"Just the knowledge that every minute spent in your presence becomes the new greatest minute of my life."
How could you miss the aftermath of the breakout? The explosion from the sign falling on the truck was priceless. In fact, that whole scene was priceless.
Bolt, trying to escape from the animal control van, and finding the compartment resistant to his head: "Must be made of Styrofoam!"
What the Agent said to Penny after he gave her a dog that wasn't Bolt as an attempt at replacing him.
Agent: Y'know, when I was little, I wanted a bicycle for my birthday, but my parents gave me a baseball glove. So, y'know what I did? I PRETENDED that baseball glove WAS a bicycle. And I rode it to school everyday. True story.
When Mittens is teaching Bolt how to behave like a normal dog:
Mittens: They do things like—
(cut to the two of them standing before a toilet)
Bolt: Out of this?!
The Los Angeles pigeons who spot Bolt and decide to pitch a High Concept story idea for the show. Just one word. "Aliens."