First, you must know the plot for the Mask series to understand this slip-up. In the original movie, Ben Stein's character describes to Stanley that Loki was a NIGHT god, and therefore his mask would ONLY WORK AT NIGHT!!!!

But, in this sequel, Tim's dog, Otis, wears the mask several times...and in one scene (scene no.9 on the DVD entitled "son of the mask") he is fighting with the baby. Almost half of the footage with the dog (with the mask on) is taken place in the day. I have researched this movie, and found out that its plot is in no way taken away from the original, it is just based 10 years later with different characters, making this a HUGE plot screw up!!!