When you land on a block from a sufficient height, impact particles appear. These particles are normally the texture of the block you land on. However, when you land on some non-full blocks (notably walls and fences) while touching a block that is 2 pixels or less in width (chains, iron bars, and glass panes), the impact particles use the chain/bar/pane texture instead of the texture of the block you land on.

Steps to reproduce:

1. Create a pillar of 2-pixel thin blocks (chains, glass panes, or iron bars).

2. Replace the bottom block with a wall or fence (other non-full blocks may also work but I was unable to find them).

3. Get to the top of the pillar of thin blocks and push against it so that you are touching it.

4. Fall onto the wall/fence at the bottom while remaining in contact with the chain/bar/pane pillar.