CCDD 110413—Unbelievable Being

Cool Card Design of the Day
11/4/2013 - I recently explored other options to express the illusionary creature concept. I've got three variations below all based on the core idea that an opponent must actively disbelieve the illusion's existence (but unlike Phantom Beast, they don't need a targeting effect to do it).

This first one lets them use any card as removal, but doesn't cause you card disadvantage when they do so.

The second costs them nothing but mana, but they usually don't know whether it will work or not each time they try, which makes waiting until the last moment dangerous.

The simplest method requires no cards and involves no chance. It's simply very expensive / very color-intensive. You would obviously only use hybrid mana in a set that already has it, but I like that it's easier for a fellow blue mage to see through your illusion. In a regular set, you could just set a high colorless cost. You could set a static cost like {3}{U}, which might cause some interesting sideboarding choices.

Which execution do you prefer? Do you have an even better one?

EDIT: Here's a triggered version of the first execution which isn't shorter but should be much clearer.

Here's my favorite iteration which this last re-working led me to:

This last version obviously shares a lot in common with Mana Leak / Force Spike, which is a neat design asthetic, but dangerous just like those cards are. The difference is that you're not responding to an opponent's spell with Unbelievable Being but casting in on your turn. In Limited, you'll only get to do that safely on turn 2 if your opponent cast a spell (probably a creature that can trade with it) and thus is less likely to be blown out by an aggressive early creature. In Constructed, you'll often cast it safely, but your opponent will usually have an answer. Where it really gets scary, ironically, is when you play it alongside Mana Leak and Force Spike (and Unsummon).