Irresistible Will

In your Shooting phase or the Fight phase, select
one SYNAPSE unit from your army that has not
been selected to shoot or fight this phase, and
one enemy unit within 24" of and visible to the
SYNAPSE unit. Until the end of the phase, each
time a friendly TYRANIDS model makes an
attack that targets that enemy unit, if the
attacking model's unit is within 6" of your
SYNAPSE unit, re-roll a Hit roll of 1 and re-roll
a Wound roll of 1.