Black cover possibly scifi book before the year 2008

When i was a kid, 2nd grade, i found a book in the school library, went to go read it and as i was on chapter 1, a teacher took it from me saying it was too mature for me.

This was in northern California, 2007 or 08

All i remember was it had a predominantly black or dirty black soft cover, the cover was like a plastic film that slightly overhanged and had rounded edges. It had some form of large maybe bulbous-like alien or ufo i believe and possibly green lettering or green throughout the cover.. the book was probably around 250-400 pages.

All i can remember and its been bothering me ever since. Ill remember the cover when i see it tho. I even asked Grok to help solve it and he was having a hard time, so thought id come here.