Spire Serpent still has defender if you control three or more artifacts, although it will be able to attack.
01-06-2011
wotc
If Spire Serpent has been declared as an attacker, and you stop controlling three or more artifacts later in combat, Spire Serpent continues being an attacking creature until combat ends.
Random a card of Magic: The Gathering (MTG), but you can also roll the D20 dice, random a Planeswalker, have fun with the random rules and more.