I got more information from some Norwegian experts, they say that if it is slimy at this stage, it is probably Mucilago crustacean , or Dog Sick Slime Mould (not very poetic name, I prefer the Norwegian one, ‘heksespytt’, or wich’s spit); if it is dry and woolly, then it is not a myxomycete. Many photos on the Internet certainly resemble your cotoneaster decoration.