[Lancashire Lad]

Hi and welcome to WAB.

You photo is fairly typical of the slime mould Enteridium lycoperdon.

Commonly found on dead wood, the mould goes through several stages, including a whitish (or sometimes pale yellowish, pale orange/flesh coloured "tapioca" like jelly, followed by the typically silver or sometimes greenish hard skin stage, finally becoming dark brown, enclosing dark brown/blackish and quite solid spore mass.

Regards,
Mike.