When something completely takes all of a person's attention, you can say that that person has been "sucked into" it. For example, you might get sucked into:
- a really addictive crime novel
- a long and complicated video game
- an exciting but very competitive industry, like the entertainment industry
- news about a famous murder trial
Another meaning of "sucked in" is to be fooled by someone's lies and false promises:
Don't get sucked in by credit cards offering free airline miles or other perks.
Being "sucked into" something is usually negative, whether it's used with the first or second meaning.