It's not immediately obvious if an address is a burn address
Any address can burn coins (just delete your private keys and it's burned!), but what makes burn addresses special is that it's obviously not randomly generated. I've used an address starting with 166666666 in the past, which wasn't a burn address. But if it would be 20 more sixes, it becomes very unlikely to own it's private key.
For fun:
Create your own Bitcoin burn address.
Yep but I wasn't sure if its easy to create a something to identify a particular pattern within the address that makes it likely to be a burn address. I have doubts about its reliability; addresses with a lot of the same continuous characters would definitely be a burn address but I've seen burn addresses which are a lot more unique (not vanity).