Create X 1/2 green Spider creature tokens with reach, where X is the number of creatures attacking you. Prevent all combat damage that would be dealt this turn by non-Spider creatures.

Reach

Whenever an opponent casts an instant or sorcery spell, create a 1/2 green Spider creature token with reach.

{T}: Add one mana of any color in your commander's color identity.

Destroy target permanent an opponent controls. Its controller may search their library for a basic land card, put it onto the battlefield, then shuffle.

Destroy target permanent. Its controller creates a 3/3 green Beast creature token.

Bojuka Bog enters the battlefield tapped.

When Bojuka Bog enters the battlefield, exile target player's graveyard.

{T}: Add {B}.

{2}, {T}: Add {B} for each Swamp you control.

The owner of target permanent shuffles it into their library, then reveals the top card of their library. If it's a permanent card, they put it onto the battlefield.

{T}: Add one mana of any color in your commander's color identity.

({T}: Add {G}.)

({T}: Add {R}.)

Search your library for a Forest card, put that card onto the battlefield, then shuffle.

({T}: Add {B} or {G}.)

As Overgrown Tomb enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.

Destroy target artifact or creature. It can't be regenerated.

Reach

When Skyfisher Spider enters the battlefield, you may sacrifice another creature. When you do, destroy target nonland permanent.

When Skyfisher Spider dies, you may gain 1 life for each creature card in your graveyard. If you do, exile Skyfisher Spider from your graveyard.

{T}: Add {C}{C}.

({T}: Add {B}.)

{T}: Add {C}.

{T}: Regenerate target Insect, Rat, Spider, or Squirrel. (The next time it would be destroyed, instead tap it, remove it from combat, and heal all damage on it.)

Vigilance, reach

All creatures attack each combat if able.

Whenever a creature attacks you or a planeswalker you control, put a +1/+1 counter on Thantis, the Warweaver.

Each land is a Swamp in addition to its other land types.

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)

I -- Urza's Saga gains "{T}: Add {C}."

II -- Urza's Saga gains "{2}, {T}: Create a 0/0 colorless Construct artifact creature token with 'This creature gets +1/+1 for each artifact you control.'"

III -- Search your library for an artifact card with mana cost {0} or {1}, put it onto the battlefield, then shuffle.

Each land is a Forest in addition to its other land types.

({T}: Add {B}, {R}, or {G}.)

Ziatora's Proving Ground enters the battlefield tapped.

Cycling {3} ({3}, Discard this card: Draw a card.)