Hes getting a "seal" of approval and stealing the spotlight.A massive sea lion nicknamed "Chonkers," estimated to weigh between 1,500 and 2,000 pounds, is drawing crowds to San Franciscos Pier 39, where the rare Steller sea lion has been spotted lounging among much smaller California sea lions, according to The Marine Mammal Center.The outsized marine mammal has quickly become a must-see attraction, with visitors flocking to the popular waterfront destination for a glimpse of the unusually large animal, whose presence is rare compared to the piers typical sea lion population.The massive sea lion dwarfs the smaller animals that typically crowd the docks.APEX PREDATOR THREATENING NORTHWEST SALMON SPARKS RARE BIPARTISAN PUSH TO 'KILL MORE'"Hes like a Volkswagen! Hes so huge!" said visitor Oluwaseyi Akinbobola, who rushed to the pier hoping to see the animal after hearing about it.Experts estimate Chonkers weighs between 1,500 and 2,000 pounds and likely traveled from waters off Washington or Oregon, said Laura Gill, public programs manager at The Marine Mammal Center in nearby Sausalito.Visitors snapped photos and gathered along the pier Thursday morning as the enormous sea lion flopped onto the docks, surrounded by dozens of smaller California sea lions that typically inhabit the area.THOUSANDS OF MYSTERIOUS SEA CREATURES 'LITTERING' COASTAL TOWN: SEE THE PHOTOSThe protected docks offer shelter from predators and rough waves, along with an abundant food supply including anchovies, herring and rockfish, Gill said."Theres plenty of food in San Francisco Bay for them a lot of easy prey for them," she said.Despite his size, the Steller sea lion has been seen attempting to snuggle among the smaller animals for warmth, though he "sticks out like a sore thumb," Gill said.FIRST EMPEROR PENGUIN KNOWN TO REACH AUSTRALIA FOUND ALIVE ON TOURIST BEACHSea lions have gathered at Pier 39 since shortly after the 1989 Loma Prieta earthquake, whose epicenter was in nearby Santa Cruz County, when a small number of animals began occupying the docks before growing into a well-known tourist attraction.Chonkers has been most visible in the early morning hours and can be difficult to spot later in the day, adding urgency for visitors hoping to catch a glimpse.Officials say it remains to be seen whether more Steller sea lions will follow, but for now, the oversized visitor has become an overnight, and perhaps overweight sensation at one of San Franciscos most popular tourist destinations.The Associated Press contributed to this report.