New gimmick that brings homing red Fish Missiles from off-screen (from Fluff8836)

[TrashboxBobylev]

The three names I thought of like "Fishy" or "Tracked" or "Locked-on" mean the same thing.

What if there is a depth where suddenly there are Fish Missiles appear from off-screen every 10 seconds or so, one at a time? The Fish Missiles from the Depth 10 boss fight?

Like Hellish, another gimmick that forces you to keep moving, but these are homing missiles that can be shot and destroyed.

May need to set the Fish Missile sprites to a different sheet like NpcSym and edit npc.tbl for this.