What once soared high above Tarkir is now reduced to a seat.

Dragon Throne of Tarkir

Equipped creature has defender and "{2}, {T}: Other creatures you control gain trample and get +X/+X until end of turn, where X is this creature's power."
Equip {3}

The List

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Khans of Tarkir Promos

Khans of Tarkir

The value of X is determined as the activated ability resolves. If the equipped creature isn’t on the battlefield at that time, use its power the last time it was on the battlefield to determine the value of X.

If the equipped creature’s power is negative while resolving the activated ability it gains, X is considered to be 0. (This is a change from previous rulings.)