Notes from AllergicToRye on discord
Aussie%

Frayed Rosary String on first drop down +30 (30)
Moss Mother

Beastfly Pogo
Silk Spear

Bell Beast [autosplit is after Silk Heart]
Save and Quit after Silk Heart

Navigate to Hunter's March (optional safety bench in the Straight Pin room)

Hunter's March Skarrgard 
Pogo up and past the Skarr Stalker and grab the Rosary Necklace +120 (150)
Continue to the right and enter the Shakra Arena

Unlock the trapped bench
Navigate to Ant_Merchant and take damage from both traps. Die in spikes before merchant.
Repeat and cocoon skip to merchant (Be careful not to pogo or slash too close or he gets scared and runs away)
Buy Boomerang
gg