Luminescent/Glow Snail

It was stated by the developers that dynamic lighting was infeasible at this point in time, but what if the mob in question didn't actually produce light or use dynamic lighting? You may be wondering how a mob suggesting that is called Glow snail gets it's name of it doesn't produce light? Well the awnser is a simple one instead of the snail producing light the as the snail moves it lays down a trail of glowing smile that emits a light level of 9 after a bit of time that drops to 6, then 3, and then it disappears. This mob would be an ambient cave mob to provide some light in bigger caverns.