Cheapest priced copy (Modern Horizons 3): $0.35 at Card Kingdom, near mint, their price list as of .
Reef Worm 
Creature — Worm · 0/1 · Rare · Commander 2014 · #16
When this creature dies, create a 3/3 blue Fish creature token with "When this token dies, create a 6/6 blue Whale creature token with 'When this token dies, create a 9/9 blue Kraken creature token.'"
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
4 printings · $0.35 to $1.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Masters 25 | 70 | Rare | $0.49 | $1.49 |
| Commander 2014 | 16 | Rare | $0.49 | — |
| Commander 2021 | 127 | Rare | $0.49 | — |
| Modern Horizons 3 | 271 | Uncommon | $0.35 | $0.49 |