What is this and why would it be there?

My guess is this'll be the boogie monster under the goop! 70 1/2 340 block.View attachment 1715417144 View attachment 1715417145

Living in Ohio I have seen and have had more than a couple 340 blocks and one was a T/A all cracked in the right valley just like the one in the picture. Not enough anti freeze every time, I even bought a 70 340 cuda that had froze and popped all the freeze plugs and did not break the block ! go figure.