"The shadow travels toward the apex. I predict we will soon see the true measure of darkness."

Seer's Sundial

Landfall — Whenever a land you control enters, you may pay {2}. If you do, draw a card.

Modern Horizons 3 Commander

Landfall — Whenever a land enters the battlefield under your control, you may pay {2}. If you do, draw a card.

Commander Legends

Zendikar Rising Commander

Commander 2018

Commander Anthology Volume II

You choose whether to pay {2} as the ability resolves. You may pay {2} only once per resolution.

A landfall ability doesn't trigger if a permanent already on the battlefield becomes a land.

A landfall ability triggers whenever a land you control enters for any reason. It triggers whenever you play a land, as well as whenever a spell or ability puts a land onto the battlefield under your control.

Whenever a land you control enters, each landfall ability of the permanents you control will trigger. You can put them   on the stack in any order. The last ability you put on the stack will be the first one to resolve (As a result, you can have those abilities resolve in the order of your choosing.).