Cheapest priced copy (Jumpstart 2022): $0.59 at Card Kingdom, near mint, their price list as of .
Endbringer 
Creature — Eldrazi · 5/5 · Rare · Commander Masters · #803
Untap this creature during each other player's untap step.
{T}: This creature deals 1 damage to any target.
{C}, {T}: Target creature can't attack or block this turn.
{C}{C}, {T}: Draw a card.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
6 printings · $0.59 to $2.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander Masters | 803 | Rare | $0.69 | — |
| Jumpstart 2022 | 748 | Rare | $0.59 | — |
| Modern Horizons 3 Commander | 156 | Rare | $0.59 | $2.49 |
| Oath of the Gatewatch | 3 | Rare | $0.79 | $1.99 |
| Oath of the Gatewatch Promos | 3 | Rare | — | $0.69 |
| Oath of the Gatewatch Promos | 3s | Rare | — | $2.29 |
3 rulings from Wizards of the Coast
- 22 January 2016Activating the second activated ability after a creature has legally been declared as an attacker or blocker won't change or undo that attack or block.
- 22 January 2016Endbringer untaps at the same time as the active player's permanents. You can't choose to not untap it at that time.
- 22 January 2016If an effect states that Endbringer doesn't untap during your untap step, that effect won't apply during another player's untap step.