Where's My Lasso?

So, I'm standing in the kitchen cleaning, I dunno, the counters or stovetop or something when I look over and see Keith grab my car phone charger. I almost took it away then thought "eh, he probably couldn't hurt that. THEN, a couple minutes later I hear Keith say "My lasso!" And wondering if I possibly heard him right I look over at Keith, and there he is, holding my phone charger and swinging it around like . . . well, like a lasso! Where on earth did he learn that word? I don't know! He just said it, and for the rest of the day he'd put it down somewhere and then a few minutes say "where's my lasso?"