Cheapest priced copy (The Lost Caverns of Ixalan Commander): $11.99 at Card Kingdom, near mint, their price list as of .
Herald of Secret Streams 
Creature — Merfolk Warrior · 2/3 · Rare · The Lost Caverns of Ixalan Commander · #158
Creatures you control with +1/+1 counters on them can't be blocked.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
5 printings · $11.99 to $37.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| The Lost Caverns of Ixalan Commander | 158 | Rare | $11.99 | — |
| The List | XLN-59 | Rare | $11.99 | — |
| Ixalan Promos | 59p | Rare | $15.99Out of stock | $37.99 |
| Ixalan Promos | 59s | Rare | — | $24.99 |
| Ixalan | 59 | Rare | $12.99 | $27.99 |
One ruling from Wizards of the Coast
- 29 September 2017Once a creature you control has become blocked, putting a +1/+1 counter on it won't cause it to become unblocked.