The color of the split cards is equal to the color of both halves as if they were one single card
It's also multicolored while not on the stack
These include cards such as Kozilek (card draw, counter), Deepfathom Skulker (card draw, unblockable), Sire of Stagnation (card draw), Oblivion Sower (land fetch), Desolation Twin (creature token), Drowner of Hope (creature tokens, tap), World Breaker (removal), Hideous Taskmaster (steal, annihilator), etc
You have to discard a spell, so it means 'converting a spell in your hand into 3-mana 4 damage.' If that's the case, honestly, I'd rather include a card like that from the start instead of paying 5 mana
The Golgari Swarm is represented by team Speedbrood in Aetherdrift and good power to cost ratio in cheap vanilla creatures like Jibbirik Omnivore and Kalakscion, Hunger Tyrant
Same goes for metagaming as it does for deck building: encourage opponents or prospective opponents to make unjustified, unfair misconceptions about your actions