The Lava Monster was the disguise of Arin the Windy.
Physical appearance[]
It's a large humanoid made out of dark red lava that constantly drips, it also has yellow eyes and a gaping mouth. It's body is surrounded by black smoke (which Arin used a machine inside his suit to have it happen.
Personality[]
It was a hostile entity that goes out on the attack towards anyone around the beaches in Hawaii.
History[]
Scooby-Doo! World of Mystery[]
It was spotted by Velma, who was near the volcano to study it and it ran towards the beach to attack the rest of the gang. It first targeted Daphne who was relaxing on a beach bench and scared her away, then it attacked Shaggy and Scooby which one of the two thought he was smelling smoke from a barbeque. And it then went after Fred and Makani who were just surfing, leading them to abandoned their surfboards.
Fred and Shaggy were then tasked in catching the monster, by using tanning cream making it slip. They got on their surfboards (with Shaggy not doing a good job) and were followed shortly after, Fred placed down the cream by the monsters feet making it slip and fall into the water, which was revealed that it was on a surfboard the whole time, while also having it covered up by the rushing water.
Arin unmasked.
Fred then went to unmasked the monster, which was revealed to be Arin the Windy, a legendary surfer who was trying to prevent others from beating his surfing record.
He was forgiven for his actions a couple seconds later after making an agreement that he'll teach newcommers on how to surf.