This artifact doesn't untap during your untap step.
{T}: Add {C}{C}{C}.
{3}: Untap this artifact.
Mana cost
3
Mana value
3
Printings
From
$3.67
EDHREC rank
#565
Buy
Formats
Legacy
Legal
Vintage
Legal
Commander
Legal
Rulings
7 Aug 2020
Basalt Monolith's last ability can untap it as often as you can pay for it. If you believe you've found a way to generate an unbounded amount of mana with it, you're probably right.