Stacking many anvils, then breaking the bottom one will make anvils randomly appear (for split seconds) in the air.

What I expected to happen was...:
Anvils cascade down when I break one

What actually happened was...:
Anvils randomly appearing in mid air

Steps to Reproduce:
1. Stack several anvils (40+)
2. Break the bottom one
3. Step back and watch the sky

*note this glitch is purely graphical