Pretty minimal blood in the film (unless you count the monster getting shot in the head with a spurt of yellow blood). Most of the fluids in the film are green, rather than red. The only other blood in the film is when a hazard-suit man gets slashed across the face by a clawed hand, brief blood spills out. He then gets pulled into the waste bucket and eaten alive; his green slimy severed hand flies out.
Many displays of goo and makeup not found in nature for cartoonish grossout effects.
Several scenes involving teen bullying and name calling.
At the end of the movie a mutant rat comes to life and grows.