Stanley

Stanley is a bug exterminator as well as the protagonist of the game Donkey Kong 3. In this game, Stanley uses his insect repellant to do battle with Donkey Kong and several insects in a greenhouse. Presumably, Stanley managed to defeat Donkey Kong and sent him back to where he came from. He was never heard from again after the the original Donkey Kong series..

Donkey Kong 3
Not only had insects infested his greenhouse, but Donkey Kong was trying to cause damage. Donkey Kong would pester bees in their hives to attack Stanley. Stanley would spray Donkey Kong with his Bug-Spray Gun (which was hanging from two vines) and he would be pushed upward by it and eventually end up with his head stuck in a beehive at the top of all the vines.

Saturday Supercade
Stanley made one appearance in the television series Saturday Supercade, in the Donkey Kong episode "Greenhouse Gorilla", where he's the owner of a greenhouse. Here he's seen taking care of a carnivorous plant called Herman, but then a thief (only referred once as Mr. X) steals it while Stanley is occupied bugspraying a bug. The thief then convinces Donkey Kong that Stanley is the one who wanted to hurt the plant, so he starts throwing beehives at him. Once again Stanley is too occupied fighting the bugs and lets the thief and Donkey Kong run away with Herman. Stanley then joins forces with Mario and Pauline and starts chasing them. After a confrontation at a supermarket, and one at a manor where a 'grand ball' was taking place, Pauline convinces Donkey Kong that the thief is the evil one, so they finally defeat him with the ape's help. The thief is finally arrested and Herman returns to Stanley, but Donkey Kong runs away once again. 

Donkey Kong 3 (Game & Watch)
Stanley's greenhouse was again attacked by Donkey Kong, who this time had a sprayer of his own. Donkey Kong and Stanley stood at opposite ends of the greenhouse and sprayed the bug spray at bees to move them toward one another and get them to sting the other.

Game & Watch Gallery 4
Stanley appears in this game as a playable character in a port of Donkey Kong 3 (Game & Watch) which is one of the many Game & Watch games ported into this game. A modernized version is featured, however it is set in a Ghost House rather than Stanley's greenhouse, Mario replaces Stanley and Boos and Fireballs replace the Bees.

Super Smash Bros. series
Stanley appears in Super Smash Bros. Melee as one of the many collectable trophies. Mr. Game & Watch also uses the sprayer as a weapon called Greenhouse, matching its first appearance.

WarioWare: Twisted!
Stanley appears as a playable character in one of 9-Volt's Microgames. In this he must do as he did in Donkey Kong 3 and spray Donkey Kong until he goes up and gets his head stuck in a bee hive.

WarioWare: Touched!
Stanley appears in 9-Volt's Microgame Donkey Kong 3. In this microgame, the player must blow at the microphone to make Donkey Kong move to the top, and Stanley, instead of spraying Donkey Kong with his sprayer, he blew clouds out of his mouth to make him move into a bee hive.

WarioWare: D.I.Y. Showcase
Stanley appears in one of 18-Volt's Microgames. In this game he must do as he did in Donkey Kong 3 and spray him until he goes up and gets his head stuck in a bee hive.

Greenhouse
The 1982 Game & Watch game Greenhouse has a premise, setting and gameplay very similar to Donkey Kong 3, and while the game's instructions only refer to the playable character as the "Fumigator", there is often speculation that he is the same character as Stanley despite his vastly different physical appearance and the fact that Greenhouse predates Donkey Kong 3. A 1983 Game & Watch commercial calls the Greenhouse character "Stanley", but no other official sources link the characters.