The Sword of Beheading is a Slimefun-based sword, and has the ability to create heads of players and increase the chances of getting a mob skull. It comes in the form of an iron sword, and has no other special abilities.
During the Second Era, players such as butterbrine22 and GummyGuy have had massive head collections (over 100+ heads) as the result of players volunteering to give their heads, or by collecting them using sheer force.