Potion of Diminution
Potion, rare · 2024 rules, SRD 5.2
When you drink this potion, you gain the "reduce" effect of the Enlarge/Reduce spell for 1d4 hours (no Concentration required). The red in the potion's liquid continuously contracts to a tiny bead and then expands to color the clear liquid around it. Shaking the bottle fails to interrupt this process.
Also in the 2014 rules (SRD 5.1).