I feel totally paranoid with any explanation I come up with, yet this makes NO SENSE.
Last year for Christmas my mother gave me this little 6 pack of tiny cactus plants. Cacti grow slowly, so they are all still in the same little pots they came in, waiting to be big enough to transfer together.
Today I realized I hadn't watered them for a while and went to do so. This is when I discovered one cacti does not have a pot. I truly have no idea when this changed as it's not something I'd necessarily focus on while running around, yet I have watered the plants monthly or so, which is what you're supposed to do.
They are sitting on a table by my sliding door. Therefor one explanation could be the window installers dropped and broke the pot (which would be weird since it's plastic) and put the plant back. However, the soil is pretty intact for that, although with cacti root systems I suppose it could just be held together well.
The only other things I can think of are things like the neighbor kids came in the slider if I left it unlocked at some point (likely) and took it.
How does a tiny planter walk away, leaving an intact plant and 5 other intact plants IN pots beside it?
(ETA; There is dirt scattered across the little table but it was cleverly concealed by rearranging everything on the table. Leaning strongly towards window installation team).