Intro Bot Easter Egg????

I played in Intro Bot just to screw around, I had dark seal obviously and killed the bot lane around 5 times and stacked myself up with first back . I teleported back into their second turret to get a few more Penta kills to get full item set ASAP, and I have noticed that I could tower dive anyone with only these items, I thought I was a little too tanky but I didn't bother. after we got nexus turrets I started back, and I noticed that there were items that I have never bought, which are the s that magically appeared in my inventory.

I'm really curious to see what the Riot's intention is.

If anyone got more informations about this "Easter Egg" or bug or glitch or whatever, please comment below.