Still, the high mana count here along with requiring it to deal damage, makes this a bit hard to include in a deck, but if you have ways to cheat stuff in and attack (like Sneak attack), this can work wonders even after just one hit
Decks in these formats can cost thousands of dollars, and the formats are kind of designed for veterans of the game
If you were in the same scenario but Pit Scorpion was attacking rather than the elf, youd die to combat damage before the trigger to add a poison counter went on the stack
Geistcaller is a bit more fragile than its enchantment counterparts, but it makes up for that by being able to make itself indestructible if you have a free Spirit laying around, which shouldn't be a problem in the decks that will play it
This is an easy one-two punch for temporarily removing an opponents commander or a problem creature in general, and it combines well with other ways to suspect creatures