The Denshi Bunny was a small turquoise-colored bunny-shaped Shen Gong Wu with blue eyes.
Despite having "bunny" in the name, this particular Shen Gong Wu doesn't actually turn the user into a rabbit--this is what the monks (or at least Raimundo) initially assumed. Dojo explains that the Denshi Bunny transforms the user into electricity, which later proves to be strong enough to short circuit weak conductors like lightbulbs, lamps and robots (like Jack-Bots).
It was successfully retrieved by the Dragons after defeating one of Jack Spicer's robotic doubles, while the real Jack Spicer was busy stealing their Shen Gong Wu. Later, Omi used the Denshi Bunny in an attempt to stop Hannibal Bean from becoming the most destructive force in the universe. However, this backfired when both Hannibal and Omi were turned into pure energy as a result.
While trying to fix an alternate future caused by Omi freezing himself for 80 years, the elderly Raimundo Pedrosa instructed Kimiko Tohomiko to turn herself into electricity using the bunny to find the way to Jack Spicer's Shen Gong Wu vault.