Could make an interesting Lure for Kyogre with Mirror Coat and Wacan Berry, but I think Tenta's role in Ubers is more to just Spin and Spike. O the top of my head, it can't wall anything really. Draco Meteors of 150 Base SpA are too powerful, it lacks the attack stats to sweep effectively and there obviously weakness to Thunder and EQ. I can see it switching into Scizor though, but then it loses SpD, since it can't really handle a neutral, let a lone a super effective neutral hit.
Twinks on Shoddy