It’s called ‘Gelli Baff’ : http://www.gellibaff.co.uk/
Video here: http://www.prezzybox.com/products/index.aspx?pid=4382
It’s a powder that when added to water creates a non-staining coloured ‘slime’ soap that remains a gooy slime until turned back into water with the 'dissolver (regular salt)!
I think the ‘Princess Pink’ looks a lot like the bathtub of slime that attacks Dana in GB2. 
Coz.