Fireworks, when shot from a crossbow, will ricochet off of blocks and only explode when their timer reaches 0. They also look like a slideshow in the the air, repeatedly flickering and moving slowly then fast until they explode. Im pretty sure they should be exploding when they hit something instead of bouncing off. 

Steps to reproduce this bug:

1. Get fireworks and crossbow
2. Load firework into crossbow
3. Shoot it at the ground/entity where it would phase through the entity or surf the ground