Sandy Beaches is Reef, who was dressed up as a girl to enter the Battle of the Betties. At first he was dressed up like a girl by Ripper and No Pants Lance as revenge after he wrote on their faces for a prank. After they saw him surf as a girl, they left and Reef finished the wave.
When the judge (Mal Jordan) of the Battle of the Betties female surfing competition saw him and mistook him for an actual girl, she asked him to sign up. Knowing Fin was in the contest, he entered under the name Sandy Beaches.
Bummer saw Sandy Beaches surf in the Battle of the Betties (not knowing it was Reef), so he asked her on a date; at first Sandy said no but Fin convinced him/her to go on the date. Sandy wanted Fin to come but she said Reef already owes her lunch. When they're on the date, Bummer and Sandy/Reef shared a Beaver Tail. Broseph and Johnny were there too, watching and laughing at them while also filming them to use for future blackmail. Bummer tried to kiss/makeout with Sandy/Reef, but she/he left in a hurry which made Broseph and Johnny laugh even more.
Sandy/Reef finished second behind Fin, but he was later disqualified after he accidentally ripped off his swimsuit bottom during his award acceptance speech and revealed himself to be a guy when he did so. Bummer found out that Sandy was actually Reef and vomited on the ground.