I love the basilisk arrows, but I think that some additional nuance could be added to how they behave.

1. Basilisk arrows actually turn things to stone visually. This can be accomplished by applying a grayscale visual effect to a mob's skin.

2. Basilisk arrows don't work on incorporeal entities like gas clouds. This just makes them a bit more situational.

3. If you fit a flying enemy with a basilisk arrow, they fall out of the sky, taking fall damage like non flying mobs do.

4. If a frozen enemy is killed, they crumble into stone fragments.

This would make them feel more interesting to use in my opinion. I bet nothing would be more satisfying than hitting a pyrad with a basilisk arrow and watching them fall to the ground and shatter.