This is Pretty Serious Elliot, which (and this is actually a spoiler at this point) is in my top 5 Pretty Serious polishes:
I said I was doing "semi-pastels" this week, and really I don't think this even qualifies as a semi-pastel - it's pretty bright, actually - but a lot of things people pass off as pastels around Easter-time are just as bright as this, so I decided I'd let it fly. Anyway, it's spring-like and super-pretty and that's the important part, right? It's a bright sky blue that's full of micro-sparkly stuff, and it's pretty much a core color for PS, I think - at least, it's on the classics page, which is as close as Kaz comes to "core" AFAIK. It's current, anyway. (She's also closing some stuff out at the moment, so be sure to cruise by the sale page if you go over there!)
It's not really much of a spoiler considering that Elliot was in my top 5 for 2015 as well. I've enthused about this polish at great length more than once, probably. Anyway, I'll get the rest of the top 5 up soon. (For the record, I am a big fan of PS, but they're not paying me or anything. No disclosures required here.)
Added: I found a note I'd written that said Elliot is originally from the In the Night collection in 2012 (the link goes to Scrangie's post on it).