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.