Valeant Pharmaceuticals (BHC -4.24%) is on the hunt again, and its latest target is Botox king Allergan (NYSE: AGN).

Like many would-be acquisitions, Allergan isn't going down without a fight. Taking the position that Valeant's offer not only undervalues its business but it is too risky for shareholders given the "unsustainability of Valeant's business model." Ouch!

In this episode of "Market Checkup," Motley Fool health-care analysts David Williamson and Michael Douglass discuss Valeant's latest offer, why Allergan finds it offensive, and what is next for shareholders.

Also stay tuned for Michael's in-depth interview with Motley Fool Stock Advisor analyst Brendan Mathews on Valeant and why investors need to get excited about this unique pharma stock.