Token creatures are actual creatures and they will cause relevant abilities to trigger when they leave play. For example, Massacre Wurm‘s ability will trigger when a token creature controlled by an opponent goes to the graveyard. This also applies if the source of the ability itself goes to the graveyard. If a token copy of a Pelakka Wurm (perhaps made by a Mimic Vat or Rite of Replication) were to go to the graveyard, it’s own ability will trigger and its controller will draw a card.