ELI5: Explain Like I'm 5

Topoisomer

A topoisomer is a shape-shifting molecule. It's like taking a twisty straw and cutting it open in the middle and being able to twist and untwist it. A topoisomer can change its shape because it has special enzymes that can break and join parts of the molecule so it can move around, even through tight spaces! It's like twisting and untwisting the straw just by slightly moving it around.