Genestealer Patriarch and Leech Bonder do not have summoning sickness.
You control at least one additional creature.
An opponent controls a creature.
({U} magic symbol) available.
Steps
Declare Genestealer Patriarch and Leech Bonder as attackers.
Genestealer Patriarch's first ability triggers, putting an infection counter on a creature an opponent controls.
Activate Leech Bonder by paying ({U} magic symbol) and untapping it, moving the infection counter from the opponent's creature onto another creature you control.
Activate Phyrexian Altar by sacrificing the creature with an infection counter on it, adding one mana of any color.
The creature dies, triggering Resourceful Defense and Genestealer Patriarch's second ability.
Resolve the Resourceful Defense trigger, putting an infection counter onto another creature you control.
Resolve the Genestealer Patriarch trigger, causing you to create a token copy of the sacrificed creature that is a Tyranid in addition to its other types.