Sentry Bot (Fallout: New Vegas)

Sentry bots are robots found in the Mojave Wasteland.

Normal
Sentry bots are armed with a laser minigun, missiles, heavy armor, and are very fast.

Unspecified version found in REPCONN HQ
An unspecified version can be found in REPCONN HQ. It has four wheels instead of three and an extra set of arms arching around over its back, presumably its the 'Mister Handy' version of the 'Mister Gutsy' (as in Sentry Bots being civilian or military). It could also be a prototype Sentry Bot, as they seem to have other non-existent versions (like the Protectron on wheels) on show.

Appearances
Sentry bots appear in Fallout: New Vegas, as well as Fallout 3 and Fallout 2.

Tactics
Bizarrely the Hardened Sentry Bots have a Damage Threshold of 0, meaning that they are best dealt with using hollow point rounds.

Bugs
Sometimes when killed by a critical headshot a sentry bots head will be blown off and both the head and "neck" will display bloody gore similar to that of a biological unit that has experienced the same fate. Oddly enough the the "neck" still sparks electrically. That is because the robots are half biological, if you take a closer look at the corpses you will find out.