Apepollo11

If you want the characters to be confused, but not the players, pop in some classic tropes.

Two that spring to mind:

Transporter technology - High pitched noise, swirly patterns, a vague sense of being dissolved, then the reverse.

Impossibly sterile rooms - no obvious furniture, panels on the walls automatically open to provide things, beds rise out of the floor, etc.

One of those Bugs Bunny / Yosemite Sam door-after-door-after-door affairs.

Basically have two short stretches of corridor with a door either end. The door at the far end of corridor 1 leads to corridor 2. The door at the far end of corridor 2 leads back to corridor 1.

The mechanisms triggering this are pressure plates along the centre of the corridor 2, skirting along the sides will avoid triggering the plates and allow you to go to the next room.

If a player makes a hole in the door / destroys the door entirely (which I'm pretty sure my players would), they'll see the distant room magically change to the corridor when they step on the pressure plate.

If you look for acrylic paint sets on Amazon, you'll find tons of them have reviews testifying whether or not they're suitable for minis.

I'm talking about the artist tube sets, not the pots, here.

The key factor in suitability for these is the amount of pigment. The consistency can be changed easily with water.

If you don't mind a one-use option, lots of wrapping paper has 1 inch squares printed on the back. Just buy a cheap roll and use the other side.

It rolls up and the marks don't accidentally rub off. Once you're done with it, just pop it in the recycling.