ETCHEDCheapest priced copy (Commander Masters): $0.69 at Card Kingdom, near mint, their price list as of .
Regal Behemoth 
Creature — Dinosaur · 5/5 · Rare · Commander Masters · #569
Trample
When this creature enters, you become the monarch.
Whenever you tap a land for mana while you're the monarch, add an additional one mana of any color.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
5 printings · $0.69 to $3.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander Masters | 316 | Rare | $0.69 | $1.49 |
| Commander Masters | 569 | Rare | — | — |
| Commander Masters | 651 | Rare | $2.79 | $3.49 |
| Conspiracy: Take the Crown | 69 | Rare | $1.29 | $3.49 |
| The Lost Caverns of Ixalan Commander | 251 | Rare | $0.69 | — |
5 rulings from Wizards of the Coast
- 23 August 2016Being the monarch carries two inherent triggered abilities. "At the beginning of the monarch's end step, that player draws a card" and "Whenever a creature deals combat damage to the monarch, its controller becomes the monarch."
- 23 August 2016The game starts with no monarch. Once an effect makes one player the monarch, the game will have exactly one monarch from that point forward.
- 23 August 2016Abilities that trigger whenever you "become the monarch" trigger only if you aren't already the monarch. For example, if you are already the monarch as Custodi Lich enters the battlefield, its last ability won't trigger.
- 23 August 2016If the triggered ability that causes the monarch to draw a card goes on the stack, and a different player becomes the monarch before that ability resolves, the first player will still draw the card.
- 23 August 2016Regal Behemoth's last ability is a triggered mana ability. It doesn't use the stack and can't be responded to.