1. Originating shortly after the released of the game Super Smash Bros. Melee (and resurfacing after the release of its sequel, Super Smash Bros. Brawl) this term means to suffer from one or multiple KO's, deaths, etc. from an attack that is both quickly repeated and highly potent; similar to Pikachu's Down + B special attack, Thunder.
2. Similar to calling shenanigans, but exclusively for competitive video gaming. Refers to animosty towards cheap, senseless spamming of a move or continuous killing.
1. "Balls man... my pally just got pikachu'd while running Scarlet Monastery."
2. "Dude, using that is so cheap. Every time I try to attack you, I get Pikachu'd."