Tenser's Floating Disk

1st-level conjuration (ritual)
Casting Time: 1 action (+10 min)
Range: 30 feet
Components: V S M (A drop of mercury)
Duration: 1 hour
Create 3 ft. wide disk in visible range that floats
3 ft above ground. Follows 20 ft. behind you.
If distance exceeds 100 ft, the disk disappears.
Can handle an elevation change of up to 10 ft.
Can carry 500 lb. More weight = disappears.