Never seen anything like this before -
https://www.dropbox.com/s/1iu77w5vr1mnwlh/FullSizeRender.jpg?dl=0
Surprised to say the least when I nearly stepped in it, so had to have a google to find out more. Could be Mucilago crustacea, Dog Sick Slime Mould? If it is, it should turn white with black spores in a few days apparently.
Seen on upland rough grassland currently ungrazed, approx 15 X 10 cm.