(3/31/26): I have been given credit for my original idea in another project. Epic! "It smells like tea. It tastes like tea. It looks like tea (er- well, it looks like nothing but you can see the teacup). But it isn’t tea! It’s Invisibili-Tea!" (so don’t confuse this with regular tea!)
This is my first and top favorite item that I had homebrewed. Invisibili-Tea can turn its drinker invisible for 10 minutes... (But in reality, It's a useless item in actual D&D campaigns because it would be over-powered. In the D&D campaigns I play in (and my character drinks invisibili-tea,) I turn SEMI-invisible for 10 SECONDS...)