Pikachu with 120 base speed

[Ulbricht]

Just want to ask where and how to get a pikachu with 120 base speed?

I checked serebii.net site, in gen VII dex, the pikachu has normally 90 base speed however on the same website, I searched the top 300 fast pokemon and the pikachu I saw there have 120 base speed and it has a heart icon. what could be the meaning of that? 

[Delta Blast Burn]

That is the starter from let's go pikachu

[Ulbricht]

15 hours ago, Delta Blast Burn said:

That is the starter from let's go pikachu

ow, makes sense. thanks.

[theSLAYER]

9 minutes ago, Ulbricht said:

pikachu I saw there have 120 base speed and it has a heart icon

You mean this, right:

(edit derp, didn't see the second uploaded image. Only saw the first one.)

Yup, as answered, Starter from Let's Go.

And preemptively, no, you can't hack it into non Let's Go games.