IODD is a korean manufacturer of special harddrive enclosures.
They have an LCD and controls to navigate through the files/folders stored on NTFS/FAT.
By selecting an ISO file, the drive announces itself to the computer as a CD/DVD/BD drive containing the ISO. It can also do this to emulate a floppy disk drive, and up to 4 non-/removable USB drives.
No need to hope for GRUB magic to maybe work.
Their website and documentation sucks, but the product makes you giggle at the idea of using yumi/rufus/easy2boot/looking for empty/erasable thumbdrives. The latest iteration is the IODD-MINI. Though it looks like the crowdfunding campaign botched, i just bought myself the 512 GB version off Amazon Germany this week.