Periodic Table...unstable bench

Source - Reddit

 The bench looks to be sturdily enough installed to me.

Though the table needs to be updated with the newest elements and the names for elements 110 and 111.

See, it's funny, though, because many - but not all - of the inner transition metals are radioactive meaning that their nuclei are unstable and will decay into more stable nuclei.

It's a joke that requires a little chemical knowledge but that falls apart if you have a lot of chemical knowledge.