Notes:

"Dude, there's over 40 Chryssalids on this map, plus the two Advent death squads with Sectopod support."

"More Chryssalids."

"We need to stop!"

"MOAR CHRYSSALIDS"

(coughs)

So, if you have X-Com 2 and would like to experience literally the worst thing ever, you can download The Hive mod here and it's expansion, because it can always get worse, can be found here.

It makes the Chryssalids their own faction, with numerous sub-species, base attacks and defences and other specific missions based around them.

They also attack the Advent and can join in as a third faction in fights, turning a simple gun fight into a terrifying cluster f---. Especially since the Aliens can also be turned into Chryssalids now.