pink crystaline substance in trunk

[CyG]

On my 2014 Passat TDI SE there seems to be a weird pink crystal like substance "growing" in the trunk. I have not spilled anything in trunk and it reappeared after having trunk cleaned out. Has anyone else seen this or have any idea what it could be. Thanks.
https://drive.google.com/drive/folders/1CdOJ-edbKSm1FutfWwRH4TCuIYlASrm1?usp=sharing

 

[P2B]

Leaking DEF tank?

 

[Lug_Nut]

"Growing"? As in "increasing in volume"?
I'd first suspect a spilled container, or spilled content when being poured from a container into the car's DEF tank, but if the mass is getting bigger and bigger, well, that indicates it's a continual supply and not a one-time occurrence.
Clean it and observe.

 

[ZippyNH]

Dried def tends to be white...but crystals will "grow" as the spilled def dries

 

[pedroYUL]

$2 says that's DEF, which pulled some other residue off from the liner.