Each other creature you control that's a Skeleton or Pirate gets +1/+1.
Whenever one or more creature cards leave your graveyard, create a 2/2 black Skeleton Pirate creature token. (This ability triggers only from the battlefield.)
{5}{B}: Return Skeleton Crew from your graveyard to the battlefield tapped.
If two or more creature cards leave your graveyard as a single event, Skeleton Crew's second ability will trigger once. If they leave your graveyard as separate events, it will trigger once for each event.
Resolving Skeleton Crew's last ability won't cause its second ability to trigger.