Can anyone help me ID these

Found stranded near the beach. Looks like some sort of coral or eggs? I have no idea what it is.

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if you don't know what it is leave it well alone

 

@Zigs may be able to identify these for you Sippay.

 

Looks like eroded concrete filled with lightweight aggregate (micro ballons)

Used as an insulation type infil where you don't want a lot of weight