Dead Weight

Enchant creature
Enchanted creature gets -2/-2.

Spore Crawler

Myconid Spore Tender

Infesting Spores — When this creature enters, destroy up to one target artifact or enchantment.

Tukatongue Thallid

When this creature dies, create a 1/1 green Saproling creature token.

Rot Shambler

Whenever another creature you control dies, put a +1/+1 counter on this creature.

Tendril of the Mycotyrant

{5}{G}{G}: Put seven +1/+1 counters on target noncreature land you control. It becomes a 0/0 Fungus creature with haste. It's still a land.

Broodrage Mycoid

At the beginning of your end step, if you descended this turn, create a 1/1 black Fungus creature token with "This token can't block." (You descended if a permanent card was put into your graveyard from anywhere.)

Fungal Infection

Target creature gets -1/-1 until end of turn. Create a 1/1 green Saproling creature token.

The Mycotyrant

Trample
The Mycotyrant's power and toughness are each equal to the number of creatures you control that are Fungi and/or Saprolings.
At the beginning of your end step, create X 1/1 black Fungus creature tokens with "This token can't block," where X is the number of times you descended this turn. (You descend each time a permanent card is put into your graveyard from anywhere.)