Complex sentence: Since the late 1990's, shants have become a casual fashion item and are a part of high-school popular culture; popularized by M.P. Lawrie in the time between the second and ninth grade; it got him undocumentedly massive amounts of poon.
Split into simpler sentences: Since the late 1990's, shants have become a casual fashion item and are a part of high-school popular culture. There were popularized by M.P. Lawrie in the time between the second and ninth grade; it got him undocumentedly massive amounts of poon.