Glint-Horn Buccaneer triggers, dealing 1 damage to each opponent and causing you to gain that much life.
Spider-Man triggers, putting a +1/+1 counter on Benthic Biomancer.
Repeat from step 2.
This clever loop spins up a self-sustaining engine built around counters and rummaging. By kicking things off with a +1/+1 counter on Benthic Biomancer, you trigger its ability to draw and discard a card. That discarded card immediately rouses Glint-Horn Buccaneer to ping each opponent for 1 damage, which in turn conveniently triggers Spider-Man, Peter Parker to grant life and feed a fresh +1/+1 counter right back onto Benthic Biomancer to repeat the cycle infinitely.