Through some set of circumstances, your economy-sized character finds themselves confronted by a great expanse of murky water rippling across their path. Previously this would have just been a jumpable puddle left over from a sudden rain, but right now it's an obstacle between your character and shelter. An earthworm larger than an anaconda writhes in the middle of the puddle/lake, slowly growing soggier as it awaits an inevitable and final encounter with a robin. The 'shoreline' is a muddy, sopping muck.

Perhaps a leaf and twig would serve as an improvised raft, or the worm might be used as a slimy, unstable bridge. Your characters' options depend on what size they have been reduced to. With enough time and patience, they could simply get around the lake by slogging through the muddy shore- but where's the fun in that?