Flashbang/Chaff/Flare biomod

i have been thinking about a biomod that is like a built in flare / chaff like some deep sea creatures do. They shoot out a small packet of bioluminescent material and it flashes, and I think the flash slug could be part of that scan requirement. I think it’s either a squid or a shrimp that does this, but it is a defense mechanism found in nature already and I think it would add a neat layer of evolutionary realism.

An alternate idea with a similar function would be an ink pseudomorph to distract predators.