PORTLAND — If lobsters could talk, a 10-pound critter named Nick could spin a tale about a weekend adventure that would leave his fellow crustaceans in awe.

Nick’s prospects appeared dim when he was put on display in the window of a Pennsylvania supermarket. But instead of going on from there to a pot of boiling water, he was returned to the cold ocean off Maine, where he enjoys legal protection.

The lobster was measured and found to be above maximum legal size, said Marshall Murphy, spokesman for the state Department of Marine Resources.

“Unless he decides to head south, to Massachusetts or New Hampshire, he should be safe in Maine waters,” Murphy said, alluding to size limits adopted in Maine to conserve the lobster fishery.

Nick, estimated to be at least 70 years old, was released into Casco Bay on Sunday, two days after Bonnie Hazen saw the lobster being used as a promotion for a store near her home in the Pittsburgh area.

“She got upset and wanted to protect him. She didn’t want him to end up on someone’s plate,” said Toni Leone of Gorham, who helped arrange the lobster’s flight to freedom.

After Ms. Hazen appealed to the store manager, the lobster was given to her on condition she could finance its return to a natural habitat.

A local newspaper printed the story, and Ms. Leone, who was visiting relatives in Pennsylvania, contacted Ms. Hazen about bringing the lobster to Maine.

“She was happy somebody offered to take him to Maine,” Ms. Leone said. “She just wanted to make sure I didn’t want to eat him.”

Ms. Leone and her relatives packed Nick in a Styrofoam cooler with crushed ice and lettuce, then decorated the cooler with a drawing of a lighthouse and the words “Atlantic Ocean or Bust.”

“He went end-to-end in the cooler, and that was with his tail folded,” Ms. Leone said. “It seemed like he weighed a lot more than 10 pounds. He was huge.”

The cooler was strapped into a first-class seat, free of charge, on both a USAir flight to Philadelphia and a connecting flight that arrived Saturday night at Portland International Jetport.

Nick spent the night at the Harbor Fish Market on the Portland waterfront, and the Maine Animal Coalition arranged for members of the Maine Marine Patrol to release the lobster Sunday in 30 feet of water outside Portland harbor.