An imaginary alligator who helps boaters navigate unfamiliar or dangerously shallow waters; a reference somtimes used by boaters in Florida, possibly originating from a contraction of "see" and "navigator" (Navigating by looking at the water).
“The Sea Gator kept me from hitting that rock by the sand bar."
A person who doesn't look like they belong somewhere. (Alligators don't belong in the sea, get it?)
"There was a kid with a Hollister sweater in Hot Topic today. He looked like such a Sea Gator."