I would get this checked out if happens regularly. But before you rush to the ER, let me ask you, did you eat more fruit than usual? The different smell would point in that direction. Also the runny texture. Any changes to diet can affect the colour, and texture of the faeces. The normal colour is a milk chocolate colour, and the texture should be well formed, not sticky, not too dry (no rabbit pebbles). Any darker (very dark brown, with coffee grounds appearance), or with visible blood in it warrants an immediate investigation by your doctor, it could mean changes in your bowel, could indicate early bowel cancer (very treatable if caught early). But first have a good thinking about whay did you eat in the last 24 hours.
I am a western herbalist working with natural medicine