So I am still on a quest to find an easy-ish way to dump/squirt slime and gunge on people/down their pants etc.

I saw an ad for a 'pump operated shower', which i haven't heard about before (https://www.beachsoul.com.au/) and was wondering if anyone has any experience with similar things? Obviously its meant for water, but would love to be able to use it for gunge if it is capable.

If that is similar to the ones used as garden sprayers, I doubt it would work with gunge. This is the type of thing I am referring to: https://www.amazon.com/Chapin-International-20000-1-Gallon-Translucent/dp/B000E28UQU/ref=mp_s_a_1_3_maf_1?crid=2C5CN3WDF7T9L&keywords=garden+sprayer&qid=1699010175&sprefix=garden+spr%2Caps%2C2676&sr=8-3

Have you considered a garden pond pump? Never tried it myself so I have no idea if it would work. Up to you if it is worth a $15 gamble:

https://www.amazon.com/MKUPERFECT-Submersible-Water-Fountains-Hydroponics/dp/B0BQ6K8SYS/ref=mp_s_a_1_4?crid=3O82Q6SO1R2HY&keywords=garden+pond+pump&qid=1699010269&sprefix=garden+pond+pump%2Caps%2C364&sr=8-4