Watch out ,”Rocky,” this mama seal has a strong left hook.

A monk seal named after Sylvester Stallone’s iconic “Rocky Balboa” character showed her own fighting spirit Sunday when she attacked a woman who swam too close to her newborn pup in Hawaii, a report said.

“It was a brutal attack. It was rough to watch. At one point, Rocky’s mouth got a hold of her head, and she was trying to splash and get away.” witness Rosa Timberlake told KITV. 

Rocky the seal showed she wasn’t in the mood to be bothered shortly before the attack, when she was seen “barking back and forth” looking for her newborn pup.

Once the seal realized the youngster was in danger, she threw on her gloves and stepped into the ring with the California woman.

Bystanders captured video footage of the brutal attack when the woman’s head popped out of the water, and the mama charged ready to knock her out.

The woman tried to bob and weave to shore but wasn’t fast enough for the mama seal. Luckily, a canoer blocked the seal, allowing the women to reach the shore.

The woman was taken to the hospital to treat lacerations to her face, back, and arm. 

The seal gave birth to the pup nearly two weeks ago, explaining why her motherly instincts were on high alert.

Monk seals are known to be very protective and territorial, which is why the NOAA and Hawaii Marine Animal Response have warning signs at the Kaimana beach.

“We wish the swimmer a speedy recovery, and we also urge people to follow guidance from safety and wildlife officials,” said NOAA Fisheries.

The NOAA Fisheries warns beach-goers, “If you’re in an area where mother seals with pups have been spotted, we urge you to stay at least 150 feet away from mother seals with pups on land and in the water.”