The main point of interest for OC would be the trick at this time stamp Death Knight Exploit Guide Wow Legion which allows blood death knights to acquire a ghoul/abomination. The instructions for those who don't want to watch the video:
- Change to unholy spec.
- Change to blood.
- Que for bg as dps.
- Enter bg, you'll be auto-changed to unholy. Summon minion.
- DC. Re-log and you'll be in blood spec with a minion.
There's tons of other fun stuff in the video I use to this day.