Your feet get pretty muddy right away, but once they're already a mess, you figure that it won't make any difference to go a little further.
A few minutes later, you are pretty sure you are a bit closer to the source of the light. Unfortunately, it is moving away from you. Whoever you are following must be going in the same direction. Still, if you walk a little bit faster, you will catch up to them.
You try to increase your pace, but the mud is deeper here and when you pull your feet up, there is a loud "squoosh" each time. At one point you lose your boot, and have to stop and put your foot back in it carefully, then slowly work it loose. When you look up again, the light has gotten a bit smaller and farther away. It seems to be a little further to the right, so you cut through and hope you're making up for lost time.
You travel this way for almost an hour before the Will o' the Wisp you've been following leads you into deep water and you drown.