Blast From The 70's Past

Just love this, and that's why i've kept it all these years. Bampot idea to have you squeeze the Joker's legs together to get a reaction, but its great - so too the 70's era cartoon face and how the mallet has the Joker on it, with his nose for the handle.
Why don't they make toys like this anymore?

Best ever Infantino work

Sure, he had a huge track record and did some brilliant work, but don't reckon anything topped this for me.
Its a classic, iconic image and scores so high 'cause back when i were a nipper i had this as a poster on my bedroom wall, right by the headboard.
Used to stare at it endlessly, so that's part of the appeal, and cherished it as it was signed (i think) "Best Wishes, Batman & Robin".
And i thought they'd signed it just for me.
Well, i was young.
Thing is, where did the poster come from?
It must've been about A3, which rules out coming free with the American title. Maybe a giveaway with one of the UK reprints? Or a shop bought poster?