What are those grey lumps that washed up on a beach in Penang? (poll 9667320)

What are those grey lumps that washed up on a beach in Penang?

Play-Doh

Cement

Whale turd

Clay

Natural rocks

I still say it's Fergie's lady lumps

Other:

Vote View Results

See this poll on: https://poll.fm/9667320/embed