Engineered Explosives (Original Art)
Engineered Explosives is an artifact with the Sunburst keyword ability, first appearing in Fifth Dawn. It puts down a number of charge counters, equal to the number of different colors of mana used to cast the spell on the card when it enters the battlefield. Since you can choose the value for X, it’s a very effective toolbox sweeper versus many different problematic nonland permanents (creatures, artifacts, enchantments, planeswalkers and tokens). The huge flexibility that comes with this ability makes it a frequent sideboard/main-deck inclusion across many different archetypes and formats. Since it’s an ETB (Enters the battlefield) effect with an activated ability to blow it up you can hold the activation for an opportune time. In legacy its often played in the sideboard as an effective answer versus some troublesome permanents (e.g. Chalice of the Void, Tamiyo, cheap creatures, tokens..) which makes it a perfect sideboard card in this format. Engineered Explosives is also a very common card in the modern format, where its played as a flexible, targeted board-wipe/hate card, often in Affinity decks and Urzatron variants. In cEDH decks, it serves as a cheap, colorless, tutorable answer to tokens and narrow CMC threats, while also pairing well with artifact tutors (e.g. Trinket Mage,..). Engineered Explosives is not on the reserved list and has various reprints (Modern Masters, Ultimate Masters, Double Masters,..).