Approximately half-way between Jasper and the northwest tip of Maligne Lake lies the curiosity known as Medicine Lake, which varies dramatically in appearance depending on the time of year. In early July the lake is full, as it appears here, but by the end of the summer this vantage point would show a large mud flat with small streams running through it. This has always intrigued those who have encountered the lake, and may be the source of its name (which is analogous to the term "medicine man", referencing the spirit world or the supernatural, not medicine as in pills.)
Scientists investigating this phenomenon discovered that Medicine Lake is not really a lake at all. It's essentially a flood basin, where the Maligne River dramatically widens when it hits an area where the river is forced underground, and thus is bottlenecked. During the spring and early summer, runoff from rains and melting snow raise the level of water in the basin until it forms what looks like a lake, like a bathtub whose tap fills it faster than the water can drain. Over the course of the summer, the inflow to the "lake" decreases while the underground flow of the river continues, draining the area.
If you go to Google Maps and look at satellite images of this region, you can sometimes see the "lake" in various stages of fullness as you change the zoom level.