A 51-year-old visitor from Annapolis, Md., is spending the final days of her Hawaii vacation on crutches after suffering an apparent eel bite on her right foot while bobbing in an inflatable tube off Waikiki.

Kristen Porter said she was in about 5 feet of water off Kuhio Beach Park around 3 p.m. Sunday when she felt something clamp onto her foot and then clamp on again for a firmer hold. “It hurt like hell,” she said.

Porter said she shook off the unidentified biter and saw blood in the water. She called for help and two bystanders pulled her to shore.

A city lifeguard told her it was an eel bite and directed her to a nearby urgent-care facility while another lifeguard wrapped her foot. A pair of strangers carried her to the facility, where the doctor recommended Porter get stitches at a hospital, but she declined.

The doctor told Porter eel attacks are a rare occurrence and that it could have been a shark.

Porter said local people who asked about her injury were “flabbergasted” to hear her story, “so regardless of what it was, it’s apparently not that common.”

The Star-Advertiser sent Porter’s photo of her wounds to Hawaii Institute of Marine Biology researcher Kim Holland. Holland said although he is not an expert in shark bites, he doesn’t think a shark was the culprit.

“This is based on the double row of marks on the top of the foot, which might be the teeth on both sides of the upper jaw of an eel,” Holland said in an email. “If it was a shark I would anticipate that the wound be a single line of marks in an arc.”

Either way, Porter was in good spirits despite her close encounter with a peckish marine creature.