Serpent of Yawning Depth's ability is one-sided, meaning only you get the benefits from it
Buried Alive Buried Alive is Entomb on steroids (and sorcery speed)
You can probably already see that between these two spell slots, we are already representing enough damage to kill the opponent entirely via direct damage
Then you make X 1/1 flyers with the Insect type on arrival to the battlefield
Adaptive Sporesinger Agent Frank Horrigan Atomize Blightbelly Rat Bloated Contaminator Bloom Hulk Cacophony Scamp Cankerbloom Carnivorous Canopy Contagious Vorrac Contaminant Grafter Copper Longlegs Courage in Crisis Drown in Ichor Evolution Sage Expand the Sphere Grim Affliction Gulping Scraptrap High Perfect Morcant Karn's Bastion Park Heights Maverick Phyrexian Seedling (playtest) Plaguemaw Beast Planewide Celebration Pollenbright Druid Scheming Aspirant Smell Fear Spread the Sickness Thirsting Roots Tromell, Seymour's Butler Unnatural Restoration Urban Daggertooth Vat Emergence Venomous Brutalizer Volt Charge Vraska, Betrayal's Sting Whisper of the Dross Yawgmoth, Thran Physician Yawgmoth, Thran Physician
People used it to print mana basically, which got it banned