Cheapest priced copy (Bloomburrow): $2.79 at Card Kingdom, near mint, their price list as of .
Stormsplitter 
Creature — Otter Wizard · 1/4 · Mythic · Bloomburrow Promos · #154p
Haste
Whenever you cast an instant or sorcery spell, create a token that's a copy of this creature. Exile that token at the beginning of the next end step.
Legal inCommanderBrawlStandardPioneerModernLegacyVintage
Not legal inPauper
4 printings · $2.79 to $6.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Bloomburrow | 154 | Mythic | $2.79 | $3.49 |
| Bloomburrow | 319 | Mythic | $4.49 | $5.99 |
| Bloomburrow Promos | 154p | Mythic | $4.49 | $5.99 |
| Bloomburrow Promos | 154s | Mythic | — | $6.49 |
4 rulings from Wizards of the Coast
- 26 July 2024If Stormsplitter splits… er, leaves the battlefield before its triggered ability resolves, the token will still enter as a copy of Stormsplitter, using Stormsplitter’s copiable values from when it was last on the battlefield.
- 26 July 2024In the unusual case where Stormsplitter becomes a copy of something else while its triggered ability is on the stack but before it resolves, the token will enter as a copy of whatever Stormsplitter is copying.
- 26 July 2024The token doesn’t copy whether Stormsplitter is tapped or untapped, whether it has any counters on it or Auras and Equipment attached to it, or any non-copy effects that have changed its power, toughness, types, color, and so on.
- 26 July 2024The token copy will have Stormsplitter’s abilities and will be able to create copies of itself.