Help 1yo male has lost the plot!

[Blayd]

Iv been taking blayd everywhere with me and hes never had a problem with a person or a dog maybe a playful bark everynow and then but no aggression.

Last week a koala came into our house at 2 in the morning (very random as we live in an open urban area) but he didnt touch it just growled etc. The next day we saw a huge great dane probably over 40" at the withers and they sniffed each other for a bit the blayd went absolutely physco and i had to pull him away and walk off.

Now every dog he see's he trys to kill and goes absolutly physco at and now he did it to a person this morning i think im going to have to get a muzzle