No one likes it when a missile doesn't hit its mark. Especially when said missile explodes in your face. I was brainstorming a way to fix this and I think I might be onto something.
This missile behaves like the Scorpion and Assassin that are already in the game, except it doesn't blow up when it hit an obstacle. Rather, it drills through it. Once locked-on, the "Popper" missile will drill through anything between it and its target. If the Scorpion was the Green Shell, the Popper would be the Red Shell.
This would also remove the need to make the smart missile A.I.
Maybe it could drill through shields without breaking them. A Rock-Paper-Scissors relationship could justify its existence.