Fuligo septica

Not a fungus but a slime mould (or, technically, a myxomycete) and a very plausible guess as to species is Fuligo septica. At the moment it looks like it's changing from the mobile phase to the stationary sporing stage. If it doesn't rain over the next day or so you might see it complete its development. If it's Fuligo septica you'd end up with a mass of powdery, blackish-purple spores held within a thin and brittle casing. So, keep an eye on it and it may be worth another photo.

Many thanks Heino, yes I'll keep watching it, and take and post photos.

2nd picture, 24 hours later, its changed into a little pile which resembles pooh

No picture, 48 hours later it has disappeared.

It looks like the second photo shows the outer casing developing. In Fuligo septica that casing may be white, pale to dark brown or purple or the odd other shade or two. You say that it had disappeared 48 hours later and that makes me think that this colony completed the mobile-to-sporing stage development. In the sporing stage the casing is very brittle and easily broken by heat (such as that of a bright, warm, sunny day) or impact (e.g. falling twig, raindrop, animal). Once the casing has broken the spores are easily dispersed by breezes or washed away by rain. If you look closely at the spot where there has been a sporing stage, you may see a dark coating, since a good number of spores may remain trapped by mulch, debris, rough ground etc. If you see anything (and how much you see) depends on just how much wind/rain there has been, the roughness of the surface and so on. Occasionally I’ve seen a slime mould in which the mobile-to-sporing change had been aborted, leaving a shapeless blob of more or less homogenous texture. Given what you’ve seen, over the 48 hours, I’ll call this Fuligo septica since that is highly plausible – but there’s still a chance I’m wrong.