Errant Ephemeron is a common Creature — Illusion card from Time Spiral (TSP), collector number 60. Current market price: $0.05 (foil $0.37), TCGplayer market prices via Scryfall.
Flying Suspend 4—{1}{U} (Rather than cast this card from your hand, you may pay {1}{U} and exile it with four time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost. It has haste.)