This seems like the reason why ETC is currently outperforming the bulk of the altcoins.
Callisto will probably be around the $7-10 mark because of the rise from the bottom that ETC's had. Once the airdrop occurs I think that at least some ETC holders will dump their coins straightaway since they've already got the airdrop coins, leading to a correction.
So essentially, since callisto depends on how much ETC you have, once its airdrop occurs its value will be taken out of the actual ETC.
ETC, in the mean time could get to $30 if hype for callisto continues.