Gelli Baff 300G (1 Bath) Gelli Baff is the totally unique bath time product that lets you turn water into goo... and then back again! Turn bath time into fun time with Gelli Baff! Gelli Baff turns water into colourful goo and back again - providing you with 100% safe bath time fun. Simply fill your bath with warm water, sprinkle the goo former over the surface of the bath and leave it for two minutes. Watch in amazement as your boring bath water magically starts to turn into a fun, thick goo. Then stir well, get in and have fun! When the fun's all done, add the dissolver sachet and the goo disappears.