So, you might be wondering what you're looking at right now. This, my friends, is what I call a "dorf moment". The capital E represents a two-headed giant, the white stuff is mist and those smiley faces are drowning dwarves. Now dwarves can't swim, but they can desperately thrash towards the shore. Usually these surface-level puddles, like the one you see here, have upward slopes on their edges which allow the dwarves to safely climb out of the water. This one is different though, because it doesn't have those slopes. Essentially, this is a smooth pit halfway full of water.
And again, you might be wondering why the dwarves are drowning in there. You see, a little while ago this giant entered my map. I shored up in my fortress and locked it out of the fort, so it went on a rampage on the surface. It attacked an echidna(basically an exotic hedgehog) which jumped into the water pit in an attempt to save itself. It didn't help and a little while later it died from a crushed torso. For some reason this brought the enormous giant to a standstill and it refused to move even when it saw my civilian dwarves walking near it. I. taking an advantage of this opportunity, formed a squad out of random nobodies and ordered them to charge at the giant. They charged alright, charged straight into the pit. Now 7 dwarves are drowning while a two-headed giant stares at them from the grassy edge and there is essentially nothing I can do to save them, because any miner who would attempt to dig out a safe passage out of the pit would get scared by the giant and run away.

Losing is !FUN!