just like everything in life, this fight is better with friends (if you want speed and effectiveness)
Summon someone, spam attacks at gascoigne, wait for other person to spam attacks, spam attacks on gascoigne while he's distracted, repeat until he enters beast mode, use music box and do some heavy attacks to obliterate

Strategy 6: Get him caught on the stairs banister and 100% cheese him with molotov AOE like the hitless runners do.

Molotov cocktails go boom

Hot

the first time I fought him and managed to get him down to his beast phase I backed him against the wall of the stairs and he glitched through the floor and fell out of the world and I won by default. I felt dirty after that victory but I guess that is technically a possible strategy

I'm a kid playing Bloodborne for the first time, no joke, I don't use summons and I beat the OoK and father Gascoigne on the second try.

the key to this guy is aviserolling