Pirate Party Skull & Crossbones Invitations in A Bottle (12 Pack) Skull & Crossbones Invitations In A Bottle. Set sail for fun! Announce your pirate bash with these skull and crossbones invitations Each 7 1/2" plastic bottle with a cork includes assorted novelties and a paper invitation. Consult your local Post Office for mailing requirements and costs. 12 Pack. Simple assembly required.