[[Runed Stalactite]] and [[Amoeboid changeling]] would work too!
MTG
Magic: the Gathering discussion
General discussion, questions, and media related to Magic: the Gathering that doesn't fit within a more specific community. Our equivalent of /r/magicTCG!
Type [[Card name]]
in your posts and comments and CardBot will reply with a link to the card! More info here.
@jake_eric
Any counter doublers or increasers with these two would go infinite if that is what you are looking to do.
For example with [[hardened scales]] on board you would pay one mana and tap the crypticfor two +1/+1 counters. Then you could pull both off for 4 mana and use 2 to untap and one to activate again.
[[Hivestone]] is a sliver specific ability to convert all creatures into slivers. [[Artificial Evolution]] is also a fun option for changing a creature type on a spell or permanent into something else.