What you can see here is a nice try.
Before backing it used to be a well shaped FIMO cube. FIMO is some kind of clay which can be backed at 110 °C. In a few blogs you can read something like "FIMO accidentally backed at 200 °C - no problem". This is not true. At around 180 °C the FIMO gets bubbles and deforms. At 200 °C it starts to smoke - smells very unhealthy!
After opening every window I can find, I tested its consistency: No good!
So to everyone trying to use FIMO as isolation of your hot end: Keep your fingers off!
Greetings to everyone