A very odd species which looked exactly like the expanding foam used in cavity wall insulation oozing from the bark of a very old and recently dead perry pear tree.

Thanks to user Fenwickfield at iSpot I now know that this is Slime Mould Reticularia lycoperdon previously classified as Enteridium lycoperdon. Slime Moulds are a strange class of amoeboid protozoa, previously thought to be fungi but now known to be Myxomycota, which are organisms which prey on microbial food webs. This particular species is a bacterial predator and usually very tiny and unlikely to be seen, but this particular stage of it’s life cycle is a fruiting body known as a sporangium. This is a globular formation which swells up to around 50-80mm (this was near to the top end of that scale), whereupon it hardens and then eventually splits to release brown mass of spores.

I’ll try to return and take a few more pictures to illustrate more fully.

Slime Mould (Reticularia lycoperdon) by blackartz