You brought all the surplus pumpkins home and left them lying about. Then the seeds sprouted and started growing out of control. You guess that's what happens when you introduce nonindigenous FLORA into the wilderness.
Hey check it out. Every week we'll be revealing some new troll characters from Hiveswap until Act 2 is out. Follow the Troll Call here, and meet the first two here. Expect a few more surprises like this to drop in coming weeks.