Gravekeeper's Watcher

Level 4 DARK/Spellcaster Effect Monster
1000 ATK / 1000 DEF

During either player's turn, when your opponent activates a Spell/Trap Card or monster effect that could make them discard when it resolves: You can send this card from your hand to the Graveyard; negate the activation, and if you do, destroy it.

Rulings – Yugipedia

Printings:

Pharaonic Guardian: PGD-064 (Rare) - 2003-07-18
Dark Revelation Volume 1: DR1-EN012 (Common) - 2005-03-19
Legendary Collection 3: Yugi's World Mega Pack: LCYW-EN186 (Common) - 2012-09-29

Prices:

Cardmarket: 0.35 €
TCGplayer: $ 0.53