Today I looked at mons in a gym and noticed one was named with the letter "t" followed by 13 numbers that seemed random.  When I entered battle, the name changed to letters, and the new name was derogatory towards another player.  How are people doing this?  
EDIT: Changed redaction to only the other player's name.
[![enter image description here][1]][1]


  [1]: https://i.sstatic.net/p6Lz2.jpg