Astute Lexmechanic

Canticle (You may tap this creature. If you do, you
gain 1 counter of Maintenance, then trigger any
relevant Canticle effects. All counters of Maintenance
are sacrificed during the end step.) Once you have 5
or more Maintenance counters, add
{c}{c}{c}{c}. This mana doesn't drain until the
next end step.
{t}: Add {c}.