They usually employ a sense of humor, irony, sarcasm, and/or hyperbole while addressing a very serious issue.
Fabrizio is an illustrator that focusses on current events. She has been featured on NPR and a variety of other news outlets... Her Wordless News project (where she illustrates one headline each day) is awesome.
A cartoon depicting the history of conflict in the Middle East, in 3 minutes.
WARNING: this cartoon is (understandably) violent.
Illustrated by Nina Paley (here is the explanation of the cartoon).