If your deck is trying to infinite combo people with this, they should often help sort out if you are playing in the right environment
Since only black mana can be used for Crypt Rats, it's often played in decks that primarily use black mana, as the more colors you add, the harder it can be to activate
They are best in the more creature focused ones for the obvious crew reasons
Copying Objects 707 : This artifact becomes an X/X Construct artifact creature until end of turn. Clone is a creature that reads, You may have this creature enter as a copy of any creature on the battlefield. After a Staff has become a 5/5 Construct artifact creature, a Clone enters the battlefield as a copy of it
It's hard to see in the picture below, but I thought that the foil cards were a bit harder and less clearer to see through the sleeves
Creatures with evasion are very welcome, as well as equipment that provides evasion