In a defensive situation this is better than Pacifism a lot of the time but that doesn't stop it from being a bad effect overall
The World Tree Plane: Nordrassil When you planeswalk to The World Tree, or at the beginning of your upkeep, put an age counter on The World Tree, then create an X/X colorless Titan creature token, where X is equal to the number of age counters on The World Tree
If you want to upgrade your Tyranid Swarm deck a little, try adding some cards that help spread and add more counters to your creatures, like Unbound Flourishing and Inexorable Tide
Or at a minimum deal a bunch of damage and gain a bunch of life
Honorable Mention #2 (#13 Overall) - Underrealm Lich Another 5-drop, 4-power Lich
It's a win-win for you, and an extremely fun and playable card