Cheapest priced copy (Urza's Saga): $3.99 at Card Kingdom, near mint, their price list as of .
Sporogenesis 
Enchantment · Rare · Urza's Saga · #273
At the beginning of your upkeep, you may put a fungus counter on target nontoken creature.
Whenever a creature with a fungus counter on it dies, create a 1/1 green Saproling creature token for each fungus counter on that creature.
When this enchantment leaves the battlefield, remove all fungus counters from all creatures.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
1 printing · $3.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Urza's Saga | 273 | Rare | $3.99 | — |
4 rulings from Wizards of the Coast
- 4 October 2004If more than one Sporogenesis is on the battlefield and a creature with fungus counters on it leaves the battlefield, each Sporogenesis will put a Saproling onto the battlefield for each counter. In other words if there are N copies of Sporogenesis and the creature had M fungus counters, you get N * M Saprolings.
- 4 October 2004If one Sporogenesis leaves the battlefield, all fungus counters are removed even if other Sporogenesis cards are on the battlefield.
- 4 October 2004Adding a counter is optional. If you forget to add one during your upkeep, you cannot back up and add one later.
- 4 October 2004If a non-creature with fungus counters on it leaves the battlefield, there is no effect.