Bio-Cannon

On the Tyranid player's turn (shooting phase) following a slime fungus round penetration, roll again (with a -1 modifier) on the same hit location Damage Table to represent the continuing action of the slime. Each subsequent turn repeat with an additional -1 modifier. If the modified result is ever 0 or less, the slime has become inactive and no further rolls are made.

For targeting purposes the Exocrine may ignore targets that have already been penetrated. The Exocrine relies on the destructive power of the slime fungus to finish off the enemy target, so it considers one penetrating hit enough and goes off to
hunt other vehicles.