Trifortressops

Level 6 DARK/Machine Effect Monster
1600 ATK / 2800 DEF

During either player's turn, if your opponent Summoned 3 or more monsters this turn: You can Special Summon this card from your hand. If Summoned this way, it is unaffected by other cards' effects, but loses 500 DEF during each player's Standby Phase.

Rulings – Yugipedia

Printings:

Lord of the Tachyon Galaxy: LTGY-EN084 (Rare) - 2013-05-17
Dinosmasher's Fury Structure Deck: SR04-EN017 (Common) - 2017-04-13

Prices:

Cardmarket: 0.06 €
TCGplayer: $ 0.09