You might not build a deck around this cumulative upkeep card specifically, but it slips into your green lands deck at a relatively low cost
Drive to Work #102Evolution Today's first podcast talks about how the ever-changing nature of Magic impacts its design
Pyreheart Wolf from Dark Ascension develops a more solid offensive tactic by giving your entire pack menace, and its undying ability brings it right back to the battlefield should it die
The deck features a huge number of powerful cat creates many of which have strong secondary abilities include anthem effects (Kaheera, Feline Sovereign, Jazal, Regal Caracal, King of the Pride), card draw (Beast Whisperer, Feral Prowler, Generous Stray), token producers (Cubwarden, Jolrael, Leonin Warleader, Pride Warden, Regal Caracal, Garrison Cat), removal (Stalking Leonin), artifact/enchantment destruction (Enlightened Ascetic, Felidar Cub), and many more
Yes, in the same way as those collected in boosters
If either one of the targets of The Animus's last ability is illegal when the ability begins to resolve, nothing will happen when the ability resolves