Is magnesium ribbon supposed to ignite when dipped in water?

i got magnesium ribbon for christmas (ya i know. i love science and experiments so i asked for that and like potium permanganate and glycerine and stuff like that) and i saw a video that showed these guys dipping it in water and it lit up. i know its the stuff thats used in flares and i have lit it before with candles (outside) but it never worked for me by just dipping it in water. so is it even supposed to light in water or were they just being tricky little s?