Witchstalker 
Creature — Wolf
$0.25 #19122 0.27 13.1 years
Hexproof (This creature can't be the target of spells or abilities your opponents control.)
Whenever an opponent casts a blue or black spell during your turn, put a +1/+1 counter on this creature.
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Cards similar to Witchstalker expected a card that isn't here?
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Mold Adder100%
$0.11↓#14542↑0.00↓17.1 years↑
"Whenever an opponent casts a blue or black spell, you may put a +1/+1 counter on this creature."
Snake Pit90%
$0.32↑#13956↑0.06↓26.9 years↑
"Whenever an opponent casts a blue or black spell, you may create a 1/1 green Snake creature token."
Taurean Mauler88%
$0.56↑#947↑0.3118.6 years↑
"Whenever an opponent casts a spell, you may put a +1/+1 counter on this creature."
Managorger Hydra87%
$0.99↑#997↑0.48↑11.1 years↓
"Whenever a player casts a spell, put a +1/+1 counter on this creature."
Ishai, Ojutai Dragonspeaker86%
$3.29↑#4668↑0.59↑9.8 years↓
"Whenever an opponent casts a spell, put a +1/+1 counter on this card."
Eyes of the Wisent85%
$0.59↑#224720.2518.9 years↑
"Whenever an opponent casts a blue spell during your turn, you may create a 4/4 green Elemental creature token."
Sunscorch Regent85%
$0.30↑#1686↑0.2911.4 years↓
"Whenever an opponent casts a spell, put a +1/+1 counter on this creature and you gain 1 life."
Titania's Chosen80%
$0.31↑#171410.06↓27.9 years↑
"Whenever a player casts a green spell, put a +1/+1 counter on this creature."
Thundering Mightmare80%
$0.39↑#10837↑0.334.8 years↓
"As long as this card is paired with another creature, each of those creatures has "Whenever an opponent casts a spell, put a +1/+1 counter on this creature.""
Predatory Hunger80%
$0.65↑#10710↑0.00↓28.2 years↑
"Whenever an opponent casts a creature spell, put a +1/+1 counter on enchanted creature."
Forgotten Ancient78%
$0.38↑#390↑0.3723.3 years↑
"Whenever a player casts a spell, you may put a +1/+1 counter on this creature."
Freyalise's Charm78%
$0.19↓#29607↓0.00↓31.3 years↑
"Whenever an opponent casts a black spell, you may pay . If you do, you draw a card."
. If you do, you draw a card."
Medusa, Inhuman Queen78%
$0.27↑#189770.00↓0.2 years↓
"Whenever a player casts a noncreature spell, put a +1/+1 counter on this card."
Kraken's Eye76%
$0.10↓#156090.2522.6 years↑
"Whenever a player casts a blue spell, you may gain 1 life."
Purraj of Urborg76%
$0.88↑#28511↓0.2529.9 years↑
"Whenever a player casts a black spell, you may pay 
. If you do, put a +1/+1 counter on Purraj."
. If you do, put a +1/+1 counter on Purraj."
Crystal Rod76%
$0.12↓#26717↓0.00↓33.1 years↑
"Whenever a player casts a blue spell, you may pay . If you do, you gain 1 life."
. If you do, you gain 1 life."
Demon's Horn76%
$0.23↓#6483↑0.00↓22.6 years↑
"Whenever a player casts a black spell, you may gain 1 life."
Lumberknot76%
$0.11↓#15284↑0.2514.9 years↑
"Hexproof"
Sol'kanar the Swamp King75%
$0.16↓#197060.12↓32.3 years↑
"Whenever a player casts a black spell, you gain 1 life."
Citanul Druid75%
$8.63↑#28175↓0.53↑32.5 years↑
"Whenever an opponent casts an artifact spell, put a +1/+1 counter on this creature."