I had a pair of official Space Invader sneakers that would leave pixelated Space Invader stamps and ONE POINT footprints behind.

We saw these is Ravenna

Tangentially related,

one of the best things my family did visiting London last summer was to take a private bike tour of the east end street art scene with Alternative London https://alternativeldn.co.uk/

Coming from SF the ride was blissfully flat and easy and our guide (the founder) was exceptional in every respect.

It's one of the two things we tell people going to not miss... the other being, mudlarking for Victorian pipe stems [guaranteed find] and maybe something more magical [rare but happens, a local showed us an Elizabethean coin and mediaeval pin she'd found]. We went, across the river a bit west of the Tate Modern, IIRC.