u/KoddoLoL

My car recently warned for a low coolant level. I refilled it but at the same time I saw a small amount of fluid in front of the engine bay. I decided to bring the car to a mechanic and stated that the car was leaking coolant.

The mechanic got back to me today and informed that he had pressure tested the cooling system and that it was not leaking any pressure and that he could not see any signs of coolant leaking. I picked up the car drove home for 15 minutes and checked the engine bay again when I got home. Now there seems to be a bigger leak than previously. Video was taken when I got home.

Any idea what fluid the car is leaking and why? How urgent is it to get it fixed?