Cheapest priced copy (Urza's Destiny): $0.39 at Card Kingdom, near mint, their price list as of .
Incendiary 
Enchantment — Aura · Uncommon · Urza's Destiny · #89
Enchant creature
At the beginning of your upkeep, you may put a fuse counter on this Aura.
When enchanted creature dies, this Aura deals X damage to any target, where X is the number of fuse counters on this Aura.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
1 printing · $0.39 to $2.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Urza's Destiny | 89 | Uncommon | $0.39 | $2.99 |
One ruling from Wizards of the Coast
- 4 October 2004Putting on a counter is optional. If you forget, you can't go back later even if it is something you usually do.