I liked to original idea having a cool alpaka as a magnet. I modified the 3d model such that the magnet can be inserted during the print process. Not all materials seem to create a good first layer after the magnet has been inserted. ASA seems to work better than PETG.
I used these magnets here (18mm x 5mm):
https://www.amazon.de/dp/B07L7XK1N3
Add a pause using these instructions with PrusaSlicer:
https://help.prusa3d.com/article/insert-pause-or-custom-g-code-at-layer_120490
All kudos to DaBen for the model!
L'auteur a remixé ce modèle.
This remix includes a hidden cut out to insert the magnet during the print process.