How Should This Be Costed Fairly
Custom Cards forum
Posted on Oct. 11, 2015, 1:30 p.m. by CastleSiege
So I have an idea in mind for a specific creature but I'm unsure as to what its CMC should be or how much its ability should cost to activate. I'd like some help from the community to create this card. Here's a rough layout:
(Name) CMC 
(Legendary?) Creature - Siren
You may choose not to untap (Name) during your untap step.
(some number of colorless mana) (or ), Tap: Gain control of target creature for as long as (Name) remains tapped.
When (Name) becomes untapped, sacrifice that creature, you gain life equal to its (CMC or Power or Toughness?)
P/T
lemmingllama says... #3
Are you trying to make a more powerful Merieke Ri Berit?
Also a 0/1 with an activated ability of 
would be mostly fair.
For the lifegain, lifegain equal to toughness would likely be ok
October 11, 2015 1:56 p.m.
Triforce-Finder says... #4
The main difference between Merieke Ri Berit and this one is that Merieke can't untap by herself. Without support from other cards, she will only ever steal one creature. This card would allow to steal and kill one creature every turn, even indestructible ones, while providing additional lifegain. I support lemmingllama's suggestion of a activation cost. The combination of that and the casting cost should make up for getting so many steal effects out of one card. However, I'd make the lifegain equal to power or CMC, since there is a good amount of defenders with toughness far above their CMC.
Another option would be to make the activation cost 
() to steal a creature with a CMC of X.
There's a small hole in the rules text: By the time the sacrifice trigger resolves, the effect that grants you control is no longer active, but you can only sacrifice creatures you control. it would have to read "the creature's controller sacrifices it" in order to work properly.
October 11, 2015 2:28 p.m.
Izu_Korasu says... #5
it needs some kind of limiting feature
Callous Oppressor gains control, but only of a specific creature type
Avarice Totem gains control, but in exchange for the ability to get it back
Spinal Embrace gains you life/act of treasons at instant speed, but only in combat and isn't as abusable.
Beguiler of Wills, Rootwater Matriarch and Vedalken Shackles have their power limited by an outside factor.
October 11, 2015 2:31 p.m.
It's like a more broken Phyrexian Plaguelord or Royal Assassin and a more broken Merieke Ri Berit
It should probably cost something like
to cast.
The ability to control a creature could be cheap. Maybe only tap or and tap.
However you should make it such that it doesn't untap in your untap step, and you need to pay something like to untap it?
That way to steal and kill a creature would take up to 3 mana and a whole turn, which is significant. You could also only easily do it from T5 onwards.
October 11, 2015 3:46 p.m.
Izu_Korasu says... #7
Merieke Ri Berit is still tri-colored,
for casting cost
((name)) doesn't untap during your untap step.
for gain control effect
At the beginning of your upkeep, you may pay . If you do, untap ((name))
October 11, 2015 7:18 p.m.
zephramtripp says... #8
It is also possible you could give it "(Name) can't be the target of spells or abilities you control." to balance it.
October 11, 2015 9:49 p.m.
CastleSiege says... #9
So after reading everyone's posts, I've come up with a second draft:
(Name)
(Legendary?) Creature - Siren (Mythic)
(Name) Doesn't untap during your untap step.
: Gain control of target creature with CMC equal to .
When (Name) becomes untapped, that creature's controller sacrifices it. You gain life equal to its toughness.
0/3
I'm not certain if the triggered ability upon untap is worded correctly for what I want it to do. If there's a better way to put it please let me know.
Thanks for all the help so far!
October 12, 2015 1:38 p.m.
Triforce-Finder says... #10
Option a.)
: Gain control of target creature with CMC equal to X. When (Name) becomes untapped, sacrifice that creature and gain life equal to its toughness.
Option b.)
: Gain control of target creature with CMC equal to X for as long as (Name) is tapped. When (Name) becomes untapped, that creature's controller sacrifices it and you gain life equal to its toughness.
October 12, 2015 6:33 p.m.
CastleSiege says... #11
I think I like option A out of the two, thanks!
October 12, 2015 6:44 p.m. Edited.
Izu_Korasu says... #12
the gain control clause is too waaaaay too strong, you can steal multiple creatures a turn without even tapping it. making the untap text useless
so the card should tap and probably cost more
seems like you want the clause to be written more like :
: Gain control of target creature with CMC equal to . Whenever ((name)) becomes untapped, that creature's controller sacrifices it and you gain life equal to its converted mana cost.
October 12, 2015 9:21 p.m.
CastleSiege says... #13
The was supposed to be there but I forgot to add it in. My bad
October 12, 2015 10:20 p.m.
Izu_Korasu says... #14
that makes sense, the only other balancing i would consider is making the casting cost over (it allows the creature to be stronger due to being more challenging to play, but also because creatures with a-typical mana costs feel more unique/interesting)
i think legendary suits it rather well, have you come up with a name yet? Thelxiepeia and Aglaopheme/Parthenope, Ligeia, and Leucosia/Peisinoe, Aglaope, and Thelxiepeia were the names of the Sirens from the tale of Odysseus. (depending on the version, the names and number vary)
JohnnyBaggins says... #2
That card is too strong no matter how you price it. The effect is unfair and can be heavily abused by things like Venser, the Sojourner or Flickerform, even if they Murderous Cut it, they still don't get their creature back. You have to, at least, make the effect such that it ends when CARDNAME leaves the battlefield. Even with that clause, it's a Mythic Rare that has to cost
at the very least, the activation cost has to cost something like 
while not being Bolt-Proof.
I mean, after all, once the thing is going you're never going to play a relevant creature anymore. You cast a good thing, the opponent steals it with this. You cast another thing, your opponent steals it with this - it's not like you get you old thing back, no, you just lose your creature and the opponent gains a bunch of life and you've already been 0-for-2'd.
October 11, 2015 1:52 p.m. Edited.