A physician from Kansas recovering from a shark attack in Hawaii has described the terrifying moment the underwater beast seemed to appear in front of him out of nowhere . Ken Grasing , his wife and two sons had just finished snorkeling off Hapuna Beach State Park on the Big Island on the Big Island of Hawaii when a 'black cloud appeared ' in the water on Wednesday . 'The shape moved toward me quickly and it materialized into a ten- to 12-foot tiger shark , ' Grasing , 58 , said as he recovered at Queen 's Medical Center in Honolulu . Ken Grasing , from Overland Park , Kansas , was on vacation in Hawaii when he was attacked by a ten- to 12ft tiger shark . In about five-foot-deep water , Grasing saw a tiger shark , like the one pictured above , swimming around him . It bit into his left arm before Grasing hit it on the side of its head ( file photo ) The attack happened in about five-foot-deep water and there were other people around the area , according to CNN . He said it 'happened very rapidly ' and that the shark bit his left hand before moving past him . At that point he struck it on the side of the head with his right hand . 'The shark then swam around me , stayed in the area , and I stood there just yelling . It was quite the dramatic moment , ' he told CNN . 'My two boys were with me in the water and I was very concerned that the shark would attack them . ' The shark continued to cruise just outside the surf line at Hapuna an hour after the attack . A Hawaii County Fire Department helicopter tracked the animal and confirmed seeing stripes on the shark 's body . Grasing was hospitalized but is expected to make a full recovery . He suffered severe cuts on his left forearm and had an injury on his left leg , likely from being scraped by a shark fin . He 's unsure if he 'll ever go snorkeling after the shark attack . Grasing , his wife and two sons had just finished snorkeling off Hapuna Beach State Park on the Big Island on the Big Island of Hawaii when the attack occured . He 's expected to make a full recovery after suffering severe cuts to his left arm and an injury on his left leg , likely from being scraped by a shark fin . 'This is a magnificent animal swimming with great speed and power . I was really at its mercy , and if it had mind to do anything more , that would have been the end of me , ' he said . He said he made the quick decision to hit the shark on the side of the head because there were ' a lot of teeth that are sharp ' and it was 'moving very fast ' . And fortunately for Grasing , 'it did n't like what it tasted ' when it bit him , so it moved away . The tiger shark can reach up to 16ft long and is considered to be Hawaii 's most dangerous shark . There are about 40 species of sharks in Hawaii . Tiger sharks are often considered to be 'the garbage can of the sea ' , according to CNN , because they eat a wide variety of prey . In 2014 , there were six shark attacks in Hawaii , though none of them were fatal , according to the state 's shark information website . This was Grasing 's third trip to Hawaii - the family was celebrating his oldest son 's high school graduation , according to West Hawaii Today . He said despite the attack , it was still ' a great day of snorkeling ' where the family in which they saw an octopus and plenty of fish . Despite the trauma of the shark attack , Grasing said he and his family had ' a great day of snorkeling ' and that they had seen an octopus .
Ken Grasing of Kansas was vacationing in Hawaii with his wife and sons . They had just finished a day of snorkeling off Hapuna Beach State Park when Grasing was attacked in five-foot-deep water . He was bit on the left arm and then used his good hand to strike the shark on the side of the head . Shark continued to cruise around surf line for an hour after the attack . Grasing suffered severe cuts but is expected to make a full recovery .