Aplan Mortarium is a common Plane — Alfava Metraxis card from Doctor Who (WHO), collector number 568. Current market price: $0.27, TCGplayer market prices via Scryfall.
Byzantium Radiation — At the beginning of your upkeep, put an exposure counter on Aplan Mortarium. Then you lose life equal to the number of exposure counters on it. Whenever chaos ensues, create two 2/2 black Alien Angel artifact creature tokens with first strike, vigilance, and "Whenever an opponent casts a creature spell, this token isn't a creature until end of turn."