Ninjask
name: Hit-And-Run lead
move 1: U-turn
move 2: Sleep talk
move 3: Aerial Ace
move 4: Night slash/Protect
item: Choice band
ability: Speed Boost
nature: Jolly/Adamant
evs: 4HP/252Att/252spe
Strategy
The point is to send out ninjask, and hit with a powerful U-Turn, while the opponent predicts a set up for baton pass. Ninjask outruns most pokemon, including aerodacyl and Azelf, two common leads in the OU tier. If the opponent withdraws a pokemon to send out a counter, you will be able to send out a pokemon to counter it, or even just one that could defeat it. Sleep talk is to switch into breloom, to absorb sleep, and use hope to take it out with aerial ace, or to use a U-turn to escape, so you could send in a breloom counter. The fourth move is a filler, night slash to hit starmie and gengar, and protect to scout.
Team Options
This ninjask will love rapid spinners, even though it is immune to spikes and toxic spikes, it is meant to be sent into battle whenever a pokemon faints, so it will be coming in a lot, and will quickly faint from stealth rock. This set also likes entry hazards, for that will change turn some U-Turns into OHKOs. It also enjoys walls and tanks for safe switch-ins, especially heat proof bronzong, for every one will expect it to have levitate, and it resist stone edge.
Optional Changes
Instead of choice band, you could give it a life orb to allow it to use protect then attack with it's heightened speed, but it's not as effective as it's choice band. The last slot could also use mud slap to try to force switches, but this is also risky.
EVs
This set needs maxed out speed and attack to be hit as hard as possible, and maybe even scratch blissy. If you always hit first, then flee, you won't be needing much defensive EVs.
Counters
This set doesn't exactly have counters, for switching into u-turn will do nothing but let ninjask get away. Though, if it comes in against a scizor or weavile, is will come to a tough choice: Switching out risking pursuit, or using U-turn risking priority moves.