A good counter for Electruxo-M?

[Nylon]

Seems like it's Metalynx then. I really like that pokemon so I'd be happy to add one it to my team!

I breezed through Whimsicott and I saw it's offensive pressure against Electruxo-M, but,
I didn't understand how prankster worked in its favor. Sunny day? leech seed?
Well, regardless it dosen't matter. I see the offensive threat and that's good enough.
But, I might be naïve, but can an energy ball/giga drain (giga drain is the most common one I think) OHKO Electroxo-M?

Anyways, thx a lot for all replies!