The technique is very similar to shuffling the cards from above
Normally, I'd now examine the effect and history of the spiking card, but in this case it doesn't seem like anyone is purchasing it based on the rules text
You simply tap Exarch or Perstermite to make a token copy, use the token copys enters-the-battlefield effect to untap the original copy, and repeat this process over and over
It wasn't especially clear "how" this armor adhears itself to the human, so I was inspired by the specialized cells in various underwater creatures, the critters that sting and paralyze
And there's a lot of synergy between these two cards
If you can reliably give haste to other creatures, this Tyranid can continue to provide value over the course of the game