At the beginning of combat on your turn, creatures you control get +3/+3 and gain trample until end of turn.
: Until end of turn, target land you control becomes a 1/1 Elemental creature with vigilance, indestructible, and haste. It's still a land.
Partner (You can have two commanders if both have partner.)
Kamahl turns a wide board into a lethal alpha strike, pumping your whole team +3/+3 with trample every combat while his land-animation ability gives you indestructible attackers and a mana sink. You ramp hard in mono-green, flood the board with creatures or tokens, then swing for overwhelming damage or trample over blockers.
Anthem-on-a-stick gives a repeatable +3/+3 trample buff every combat, scaling brutally with go-wide boards
Land animation provides indestructible, hasty attackers that dodge most board wipes
Mono-green gives best-in-class ramp to reach his 8 mana value and beyond
Partner lets you pair him with another commander for added value or a second color
8 mana value makes him slow and a big tempo loss if repeatedly killed
Mono-green struggles with removal, card advantage, and answering combo/flyers
Highly reliant on having a board; sweepers before combat can reset your whole plan
No evasion beyond trample, vulnerable to fogs, stax on attacking, and pillow-fort decks