Eeny and Meeny seem to be Maggott's primary mutation. His secondary mutation is an obscure reference from Uncanny X-Men (1st series) #349 that was never elaborated on. Maggott's true name was revealed in X-Men (2nd series) #73. Maggott and one of the slugs were killed in the Neverland concentration camps in Weapon X (2nd series) #5. The other slug survived Maggott's death, and was last seen under Sinister's care.
He was one of many mutants resurrected by Selene and the techno-organic virus in Necrosha. It was reported that all these mutants did not necessarily die again at the conclusion of the Necrosha arc. This is presumably the explanation for his survival and appearance in subsequent issues such as Uncanny X-Men (1st series) #600 and Domino Annual #1.