Coastal New Jersey, sounds like what we used to call "quick sand".

http://www.shorenewstoday.com/middle_township/coast-guard-rescues-four-jetskiers-stranded-in-mud/article_25851782-20fa-11e5-8adb-1fdfb3a80a3b.html

On Fri, 03 Jul 2015 11:23:54 -0400, wrote:

I am still not sure this warranted calling the CG. Just wait for the
tide to float them off and get on with your life.
OMG, a half hour without water Oh the humanity!

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They were probably late for a party ashore. :-)