A creature entering the battlefield can trigger multiple abilities, as long as they are all looking for a creature entering the battlefield.
Say you control two Blood Seekers and your opponent casts Gather the Townsfolk. Each Blood Seeker would “see” two creatures enter the battlefield and trigger twice, for a total of four triggers. Those 1/1 Human tokens just cost your opponent 4 life thanks to your Blood Seekers.
Even creatures entering the battlefield simultaneously can trigger each other, so if you cast a Genesis Wave and flip over Mentor of the Meek and three Llanowar Elves, you’ll have three triggers on the stack from Mentor of the Meek, ready to let you draw three cards if you pay 1 for each trigger.
Today’s Rules Tip written by
Peter Golightly, Level 1 judge from Austin, TX