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of course, this is an "opinion", but it's the closest thing we got so far to clearing this up...1 The Tomb Spyder is a bit of an oddball and the rules for monstrous
creatures in the main rule book are not clear on this matter. In my opinion
as a hobby specialist they should be counted as an integral part of the
squad because they created it, the Spyder did not join the unit like an
independent character. Therefore the Spyder cannot be shot at or attacked
separately in close combat, however this does mean that unless the tomb
Spyder is on its own the toughness of the scarabs T3 will be used instead of
its own T6, see page 41 of Warhammer 40000. We will pass this on and get it
2 Tyranid monstrous creatures that can join units are all independent
characters and can be picked out separately in close combat, see page 51 of
Warhammer 40000. They can also be targeted separately in shooting, see page
19 of Warhammer 40000
Cheers, hear from you soon,
Games Workshop Hobby Specialist
Except for the minor fact that Tyranids have no ICs whatsoever... TMCs are TMCs and follow Codex rules (and 4thEd rules for MCs, as per the FAQ), which in no way mention targeting in CC. But I clarified that in the Rules forum, so won't go into it again.
"The meat things seek to destroy ourselves. They hunt us as we hunt them but they are weak and uncertain. The inferior flesh will be entirely destroyed, all biomatter consumed. Ourselves will fight to the last, all weak flesh must be devoured."