If I had to take a guess, I'd say no. Since you would not be negating the activation of a Spell or Trap card. You would be trying to negate the activation of an Effect Monster's effect.
Tutan Mask: "Negate the activation and the effect of a Spell or Trap Card that specifically designates 1 face-up Zombie-Type monster as a target and destroy it."
Dark Necrofear: "When this card is destroyed as a result of battle or by your opponent's card effect, it is treated as an Equip Spell Card at the end of the turn. Equip 1 of your opponent's monsters with this card. As long as it is equipped with this card, you control the equipped monster."
"Dark Necrofear"'s effect is what makes him become the Equip Spell Card. "Tutan Mask" cannot negate the effect of an Effect Monster.
Hope this helps.
Anybody feel free to correct me, like I said, I'm taking a guess based on card text.