This is getting a little scary ... Ariana Grande's new boyfriend, Saturday Night Live youngin' Pete Davidson, has already gotten TWO tattoos in honor of his new lady and they've only been hooking up for a couple weeks!

Davidson, 24, got some ink of Grande's bunny ears behind his own ear and her initials on his hand, as shown in a now-deleted Instagram from Pete's tattoo artist. Grande, 24, and Davidson made their relationship Instagram-official a few days ago with a Harry Potter-inspired post from Pete and then Ariana one-upped him with a PDA pic a day later.

Meanwhile, Davidson's ex, Cazzie David -- comedian Larry David's daughter -- posted this hilarious selfie after she learned via Instagram that she'd apparently been dumped by Davidson after two years of dating ... HIGHLARIOUS!