Typically dogs are known as ‘man’s best friend’ so in this case I would advise to watch out for false friends…
Is there anyone who you have been helping a lot lately? Anyone who could be in a position to ‘bite the hand that feeds’? If so you might want to keep an eye out for them…
Also, the bite on your leg could represent a false friend (hence why the dog appeared ‘mutated’) trying to destabilize you and/or block you from ‘moving forward’ with something… The three or four people attacking the dog could either represent people around you who will stick by and stand up for you OR it could represent the people who you are trying to harm said ‘false friend’ and who you are trying to help them from (if it’s the case that you ARE helping someone out of some shit that they are going through)…
I’d say throw up a few extra protection wards and stay vigilant in the next coming days/weeks