Rakdos Headliner
Creature — Devil
Haste
Echo—Discard a card. (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)
Caution: Audience in front row may have throats ripped out.
Ekaterina Burmak
Modern Horizons 2 (MH2)
• #210Rulings
Your permanent's echo ability will trigger at the beginning of your upkeep if it entered the battlefield since the beginning of your last upkeep, or if you gained control of it since the beginning of your last upkeep.
(wotc • 2021-06-18)
Paying for echo is always optional. When the echo triggered ability resolves, if you can't pay the echo cost or choose not to, you sacrifice that permanent.
(wotc • 2021-06-18)
Rulings
Your permanent's echo ability will trigger at the beginning of your upkeep if it entered the battlefield since the beginning of your last upkeep, or if you gained control of it since the beginning of your last upkeep.
(wotc • 2021-06-18)
Paying for echo is always optional. When the echo triggered ability resolves, if you can't pay the echo cost or choose not to, you sacrifice that permanent.
(wotc • 2021-06-18)