Krexir, Phyrexian Apprentice

Infect
Whenever you cast a creature spell you may pay 2
life. If you do that creature gains haste and infect
until end of turn. At the beginning of the next
end step sacrifice that creature.
Whenever a creature you control dies you may pay{1}{p/b}. If you do create a 1/1 black skeleton
creature token with infect.