Steps to reproduce:
Step 1: Take any tool, and put some high-level enchantments on it.
Step 2. Combine an unenchanted tool with the previous enchanted tool.
Step 3: Repeat the process(in Creative mode so you don't get Too Expensive) until the XP cost reaches 2.147 billion.
There you go! Now you can't repair or rename that tool, even in Creative mode.