Saw this at my local chinese grocery
Pretty sure it is congealed pig's blood. It's commonly seen in SEA (South East Asian) countries and Hong Kong. It is used as an ingredient in some dishes and in Malaysia, I have seen it been used in soup as well as soup based noodles.

One way to identify them is that they are always sold in cubed form.

update: sometimes, chicken blood is sold/used in the same form.