Omelet Murder
Isaac is writing about waiting for one of Amá's patented omelets when she suddenly decides to have a serious talk. "A few fart sounds later, my omelet is looking like a crime scene from one of those shows she watches when she thinks I’m not looking." This description is directed toward the omelet-serving process in which she is squeezing a plastic bottle of ketchup. The simile alludes to the way in which this attempt to extricate the ketchup winds up making it appear like a bloody mess.
Marco
This book is told with twin first-person narration. Isaac characterizes one of the fundamental differences between himself and his best friend. "Marco is a sponge and absorbs everything real quick." Isaac has trouble concentrating and focusing on any one single subject unless it is basketball. Marco is an academic who does not possess Isaac's athleticism. He is not just capable of maintaining focus on a subject, but retaining what he has learned while focusing on that subject.
Fun-Sized
Marco is short enough that he good-naturedly refers to himself as "fun sized." Isaac uses a simile to push a bit further on the physicality of his good friend. "I wouldn’t be surprised if he came home from middle school with bruises on his cheeks from all the older kids—especially the girls—squeezing his face as if he were some sort of stuffed animal." This comparison to a stuffed animal has less to do with actual physical size than with the emotional response to his stature. The point being made is that Marco does not have the appearance of anyone who could be taken seriously as an athlete, much less a successful basketball player.
Dunking
A kid named Byron prepares to show off his dunking skills. Isaac watches and describes the boy's approach to the basket as being "like watching a rocket lift off toward space." The comparison here seeks to convey the fully realized portrait of the power it takes for a school kid to lift himself from the basketball court to the rim that is perched ten feet off the ground.
Running with Arms
Isaac realizes that he has never actually seen his short, brainy friend Marco run. The reason may be that one of the few things that Marco's sponge-like brain has not soaked up is the simple mechanics of the action. "Like hummingbird wings, his arms pump up and down in a frenzy. Now if only they’d somehow sync up with his legs." The reference in the simile to the wings of a hummingbird is a commentary on how that tiny bird's wings flap so fast the human eye cannot detect them. It is also a comparison to the fact though hummingbird wings move too fast to see, the birds themselves seem to remain completely still. Marco's attempts to power his running velocity with his arms are very similar.
