The first expedition the league sent reported encountering a gigantic spore bat they'd taken to calling Sporewing. They had to leave in a hurry, so they didn't have the chance to kill him while they were here, so I figured I'd finish the job for them.
What's left of their report suggests that the creature can be found in the southwestern parts of the Dead Mire. I think Vindicator Idaar mentioned that it's to the northeast of Telredor.
Well done, <name>. I think you and I have managed to outshine a whole team of prospectors. When I get back to Ironforge, I'm sure I'll get my choice of assignments.