I decided to go my own way and create a custom hivefleet for the combat patrol.
Keeping with the "monster" theme for Tyranid fleets (they are really just misunderstood, honest) I hunted around for a suitable monster. I decided to go for something a bit different than the usual and went for looking for monsters from Asian mythology.
The result is the Itsumaden. It looks the part and is easy enough to say - could you imagine someone trying: Negoro-no-ushi-oni. :)
The image comes from the Obakemono Project, which is a great resource for Japanese mythological creatures.
I haven't bothered with any background fluff for these guys yet, though that might be getting a bit carried away...