i want to make a clear custard, any ideas / recipes for this

reason i want clear custard is for sploshing in public when its raining,

so far i have made some clear syrup by melting sugar and water but i want something to add to it to give it the same silky smoothness of custard

I'm not sure it's possible. Custard has dairy, milk fat, eggs, things that are opaque. Why not try something like undyed methylcelluose or natrosol?

Wallpaper paste is clear and pretty sticky/slippery.

You can get clear gunge, don't think clear custard would be possible.

you could do clear HEC gunge with some vanilla flavouring maybe

The main ingredient in custard powder (Asda at least in the UK) is maize starch or cornflour. Add vanilla flavouring and colouring and you have custard.

Cornflour is also used for thickening gravy.

You could try just thickening cornflour with water to see the result - it may be clear but I suspect it may turn out white(ish)

j-lube.
I use it with the missus and one bottle of powder makes ALOT - also it can be bought from amazon so is east to get hold of.
Is clear - is as thick as you make it and taste and odour free. Washes away with water too

You can guy inverted sugar in squeeze bottles in some health food store so. Some karyo syrup is clear.