Cheapest priced copy (Duskmourn: House of Horror Commander): $15.99 at Card Kingdom, near mint, their price list as of .
Giggling Skitterspike 
Artifact Creature — Toy · 1/1 · Rare · Duskmourn: House of Horror Commander · #66
Indestructible
Whenever this creature attacks, blocks, or becomes the target of a spell, it deals damage equal to its power to each opponent.
{5}: Monstrosity 5. (If this creature isn't monstrous, put five +1/+1 counters on it and it becomes monstrous.)
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
2 printings · $15.99 to $16.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Duskmourn: House of Horror Commander | 39 | Rare | $15.99 | — |
| Duskmourn: House of Horror Commander | 66 | Rare | $16.99 | — |
3 rulings from Wizards of the Coast
- 20 September 2024If Giggling Skitterspike is no longer on the battlefield when its second ability resolves, use its power as it last existed on the battlefield to determine how much damage it deals.
- 20 September 2024Monstrous isn't an ability that a creature has. It's just something true about that creature. If the creature stops being a creature or loses its abilities, it will continue to be monstrous.
- 20 September 2024Once a creature becomes monstrous, it can't become monstrous again. If the creature is already monstrous when the monstrosity ability resolves, nothing happens.