Artefacto — Equipo
La criatura equipada obtiene +1/+1 por cada criatura que controlas con fuerza o resistencia base de 1.
Siempre que un Hámster, Ratón, Rata o Ardilla que controlas entre, puedes anexar la Espada de los chillidos a esa criatura.
Equipar

.
Some creatures have base power and toughness 0/0 and an ability that gives them a bonus based on some criteria. Those are not characteristic-defining abilities, and that ability doesn't change its base power and toughness.