I think in the first game my son played with his cousin the flamer and it's template really cam into effect. A huge slew of Termagants were BBQ'd. So when I was looking in the Tyranid Codex I thought I'd found an equivalent in the Strangleweb upgrade, I was wrong, but at the time I didn't see it.
Anyway, I actually think this was the first conversion I completed. I think the Tyranid Prime was started at the same time, but of course this was so easy to do it was completed in minutes, if not seconds. All I really needed was one of the many spare Deathspitters from the original Tyranid Warriors from Advanced Space Crusade.
The arms are already attached and you just need to add a bit of pressure on the joints to bend them a bit into position and hold them in place as the Poly-glue bonds the joints. Lastly you need to ensure the Termagant's head is angled a little bit so it looks like he's actually looking at what he's about to 'gob' on!
Here's the model on it's own, instead of the Inquisitorial vid-feed...
I mean he looks impressive, especially when you're looking down the barrel of that 'thing', but there's two flaws. 1. the balance is quite difficult, he's prone to tipping and 2. The Strangleweb is effectively useless. I don't actually think my son's ever fired it, in anger or other wise.
However this forum thread seems to indicate it odes have it's uses, so long as all the planets are in alignment!