depends how you do it - if you do a tantrum and throw a bs 3 with an overhead rotation (no handle-pass), that's a whirlybird.
if you do the tantrum with a bs3 handle-passed, that's a moby dick.
if you do the tantrum and then a backside 3, as erik ruck has been, some folks argue that's a different trick, but no one's named it yet.
if you do the tantrum and then a frontside 3, you're also doing a trick that hasn't been named yet and supposedly has only recently been landed.
good luck if you can do this. can you do tantrums to blind or tantrums to fakie yet? i'd try those first if i were you...and definitely have a video camera handy so we can see it!