What does it mean by "haul ass"? Is that a slang?

What does “mad tight” mean?

"Mad tight" here is slang for "very angry". This slang term is not very common. Ex: My teacher was mad tight when I showed up late to class without my homework.

What's "Freee-Inator?"

"Freeze-inator" is not an actual noun, it's just a made-up name that Dr. Doof uses to call his gun. The name has "freeze" in it, so we can assume that it's main function is to freeze things. You'll see this kind of naming pattern a lot with children's toys, like having "splash-inator" as the name of a water gun.

What is "whereabouts"?

"Whereabouts" means "where" or "at what place". It can also be used as a noun to refer to a location or a place. It is considered very formal in American English and it is more common in British English. Ex: Whereabouts did you park the car? Ex: His whereabouts are a mystery.

Is it okay to call them "seagull" not "petrel"?

Seagulls and petrels are actually two different groups of birds, as they belong to two separate bird orders. The bird in this video is a "petrel", but these birds are different from seagulls, as they are usually much larger and have different characteristics. So if you were to call them "seagulls" instead of "petrels", it wouldn't have the same meaning. However, both seagulls and petrels have in common that they are both seabirds.

Why did he use "in little Rachel land" not "in a little Rachel land"?

Here, he is referring to a specific place, "little Rachel land." Thus, the article "a" is not needed. Ex. I need to go to Costco. Ex. I need to go to a grocery store.