Castles, dragonflies, sharks, dogs, snowmen – there was no limit on the imaginations of those who participated in the second Sandcastle Day hosted by the Onset Bay Association (OBA) on Onset Beach Saturday afternoon.

"Imagination is great," said Richard McCarthy, who lives down the street from the beach. "It's a good, wholesome day."

McCarthy was busy creating a melting snowman on a toboggan, having already finished his usual dog sculpture on the beach. Equipped with a bucket, a spoon, a fork, and a small brush, McCarthy said he was glad to build sculptures for a cause.

"It's great that the OBA is doing this," he said.

The competition, which is the brainchild of OBA member Eleanor Martin, had three categories for prizes: whimsical, artistic and original.

The winners for the first category, whimsical, were Ryan and Sean Wosney. Meredith, Will, Ava and William Regan won first place in the "original" category. Lori-Ann Mello took first in the "artistic" category.

The OBA set up a stand by the pier and handed out tools to whoever needed them, as well as buttons and bubbles for the children.

"Family fun is the goal," said Martin.

Children and adults crowded the area near the pier and Nemasket Kayak Center, beginning at 1 p.m. They encouraged and complimented each other on their creations.

Buzzards Bay resident Ian Gilligan picked a "lucky location" right against the pier, where he worked on creating a range of castles with different textures, using the greenery growing along the pier as a "jungle."

It's his first official competition though he's been building sandcastles for years now.

Even Rodney "Mr. Sandman" Johnson was there, creating a rendition of the "Jaws" great white shark. A resident of Brockton, Johnson has been doing sand sculptures at beaches all over the state for the last 10 years.

The event was free, and all were welcome to participate until 4 p.m.