The Samuroids are robots that were created by Baron Katana who wanted to destroy Western Civilization starting with Central City. The Flash was able to prevent the invasion.
A Samuroid was later acquired by Penguin. It battled Batman and the original Flash - Jay Garrick.
In the beginning of "The Button", the Samuroids were seen in a clash with the Flash.
In Other Media
A Samuroid was seen in the premiere of the fourth season of The Flash "The Flash Reborn". Unlike the comic book origins, the Samuroid was created by The Thinker in an effort to draw the out The Flash. The S.T.A.R. Labs team try their best to stop the Samuroid with just Kid Flash [who tried to be The Flash] and Vibe. Their combined efforts failed. Vibe eventually manages to get Barry out of the Speed Force, but his mind wasn't normal. The Samuroid takes Iris West hostage, which triggers Barry back to normal. Barry was successful in defeating the Samuroid, and once he brought back its head as a souvenir everyone was unaware that there was a hidden camera inside where Devoe spies on them.