Bioluminescence spotted in Wellington harbour this week. Video / Sarah Day
In the daylight it's simply an unappealing layer of pink slime floating on the water.
But at night the "discoloured smear" on parts of the waterfront in Wellington transformed into a dazzling, glowing blue, caused by bio-luminescent organisms that washed up near the marina.
Wellington woman Sarah Day this weekcaptured video of the stunning effect down at Chaffers Marina - but warns other Wellingtonians not to come looking for it.
"If I was looking for it I would look in areas between things where the water is a bit protected from the waves," she said.
By now the slime had dispersed from where she found it in the marina, but regardless, it was found in a private area that the public don't have access to.