Rod of Vapor

This wooden rod is topped with a dragon's head, carved with its mouth yawning wide. While holding the rod, you can use an action to cause a thick mist to issue from the dragon's mouth, filling your space. As long as you maintain concentration, you leave a trail of mist behind you when you move. The mist forms a line that is 5 feet wide and as long as the distance you travel. This mist you leave behind you lasts for 2 rounds; its area is heavily obscured on the first round and lightly obscured on the second, then it dissipates. When the rod has produced enough mist to fill ten 5-foot-square areas, its magic ceases to function until the next dawn.