This is indeed strange and I haven't faced this before. Files like these shouldn't exist. If I had to guess, these files seem to be result of some form of ESXi OS corruption since generic commands such as ls is giving error here which shouldn't happen.
Does these garbage files persist after ESXi is rebooted ?
Is the hardware firmware updated and in line with ESXi drivers ?
Power off ESXi and remove power cable for 10 mins. If ESXi boot is through SD card, re-seat it. Re-seat every memory modules as well.
If none of this helps in any way, it would be best to involve VMware support since it would be wise to get this sorted out to make sure it doesn't appear again in future.