You control at least one additional nontoken creature.
({1} magic symbol) if you don't control a Saproling available.
Steps
Activate Phyrexian Altar by sacrificing Slimefoot and Squee and another nontoken creature you control, adding ({B} magic symbol) ({R} magic symbol) .
When the creatures die, Golgari Germination triggers twice, creating two 1/1 Saproling creature tokens.
Activate Phyrexian Altar by sacrificing a Saproling, adding ({G} magic symbol) .
If you control two or more Saprolings, activate Phyrexian Altar by sacrificing a Saproling, adding ({1} magic symbol) .
Activate Slimefoot and Squee by paying ({1} magic symbol) ({B} magic symbol) ({R} magic symbol) ({G} magic symbol) and sacrificing a Saproling, returning Slimefoot and Squee and another creature from your graveyard to the battlefield.
When Slimefoot and Squee enters the battlefield, it triggers, creating a 1/1 Saproling creature token.