This film was recorded in 2005, moments earlier they were a number of 4X4s parked in this section of beach with guys fishing near by.
These sink holes appear every now and again along Inskip Beach near where the ferrys cross between Inskip Point and Frazer Island, They are caused by whirlpools that are generated in the deep passage every few years. The whirlpools sometimes make it shore and undermining the beach. Eventually the weight of the sand becomes to great to support itself and it collapses in a matter of minutes and has the potential to take with it anyone standing there.
Australia will try to kill you in every way.