On a trip to Belize, Central America in 2004 I found the three pictured wasps sitting completely immobile for several minutes. They were each about five centimetres long.
I later showed the picture to some people in a local village and they told me they were Strangler Wasps, that I was very lucky not to get stung because their venom constricts your throat, sometimes killing young children. I saw first hand how upset the people of the village got when one came around, they grabbed sticks, chased the creature down and killed it.
A quick web search for the term 'strangler wasp' brings up nothing.