When threatened, it slowly shakes its body to produce spores from the mushrooms growing on its back.

Lumbering Megasloth

This spell costs {1} less to cast for each counter among players and permanents.
Trample
This creature enters tapped.

Fallout

This spell costs {1} less to cast for each counter among players and permanents.
Trample
Lumbering Megasloth enters the battlefield tapped.

Once you announce that you're casting Lumbering Megasloth, no player may take actions until you're done casting it. Notably, opponents can't remove counters from players or permanents to try to change Lumbering Megasloth's total cost.

The cost-reduction ability of Lumbering Megasloth doesn't change its mana cost or mana value, only the total cost you pay. Specifically, the mana value of Lumbering Megasloth is always 12.