Genestealer Patriarch
Creature — Tyranid
Oracle Text
Genestealer's Kiss — Whenever this creature attacks, put an infection counter on target creature defending player controls.
Children of the Cult — Whenever a creature with an infection counter on it dies, you create a token that's a copy of that creature, except it's a Tyranid in addition to its other types.
Watch Out
Copies don't copy counters, equipment, auras, or other external modifications. A copy of a transformed card copies only the front face. If the copy enters the battlefield, it triggers its own ETB abilities.
'Dies' means 'put into a graveyard from the battlefield.' If a creature is exiled instead of dying (Swords to Plowshares, Rest in Peace), dies triggers won't fire. Tokens do trigger 'dies' abilities briefly before ceasing to exist.