In the past year or so, we've posted a slew of videos of Common's impressive ability to spit rhyme after rhyme completely off the top. But this latest performance just might be his best yet. While sitting in on Sway In The Morning, Com kicked a freestyle based on the phrases Sway threw his way. And as you might expect, the Chicago native had no trouble weaving "prehistoric," "forensic evidence," and more into his bars. Watch it above.